CMAA 70

90
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Transcript of CMAA 70

Page 1: CMAA 70

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(r~¡ 2000 Material Handling Industry

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Errata Sheet CMM Specification #70, Revised 2000

Under 70-3 Structural Design, page 16. paragraph 3.4.6.1 and paragraph 3.4.4.2, thefollowing corrected formulas should be used:

8 In the third quotient of the denominator, the denominator (8CC)3 should read

B(Cc)3. The first paragraph bracket should be after the B.

8 Equatíon 3.4.4.2 should read:

C'5'v = 1jz [C'5'x + ay] :t 1jz J (ax -ay)2 + 4(LXy)2 ~ aAlL.

C.The first 112 was omitted.

Errata Sheet CMAA Specification #70, Revised 2000

Under 70-4 Mechanical Design, page 33, paragraph 4.1 Mean Effective Load,the following corrected formulas should be used:

4.1.1 Kw = 2(maximum load) + (mínimum load)

3(maximum load)

4.1.2.1 K'iVh = 2(rated load) + 3(lower block weíqht)3(rated load + lower block weight) ( :-

--;4.1.2.2 Kwt = 2(rated load) + 3(trollevweiqht) }'

3(rated load + trolley weight)

4.1.2.3 K\Vb = 2(rated loal1) + 3(trollev weight + bridqe weiqht)3(rated load + trolley weight + bridge weight)

Note: In all cases throughout this specification, the upper and lower case ofthe symbol for Tau are interchangeable such that 4]'= 't.

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DISCLAIMERS

CRANE MANUFACTURER'S ASSOCIATION OF AMERICA, INC. (CMAA) .

The Crane Manufacturer's Association of America, loc. (CMAA) is an independent incorporated trade association affiliated with The

United States Division of Material Handling Industry (MHI)o

MATERIAL HANDLING INDUSTRY (MHI) AND ITS UNITED STATES DIVISION

MHI provides CMAA with certain services and, in connection with these Specifications, arranges tor their production anddistribution. Neither MHI, its officers, directors or employees have any other participation in the development and preparation ofthe information contained in the Specificationso

AII inquiries conceming these Specifications should be directed in writing to the Chairman of the CMAA Engineering Committee,

do Crane Manufacturer's Association of America, loco, 8720 Red Oak Blvdo, Suite 201, Charlotte, NC 282170

For the quickest response to technical questions use CMAA web site

wwwomhia.orgipsc/PSC Products Cranes TechOuestions.cfm or

write directly to the CMAA Engineering Committee, c/c Crane Manufacturer's

Association of America, Inco, 8720 Red Oak Blvd., Suite 201, Charlotte, NC 28217

SPECIFICA TIONS

Users of these Specifications must rely on their own engineers/designers or a manufacturer representative to specify or d.(applications or uses. These Specifications are offered as guidelineso If a user refers to, or otherwise employs, sIl or any partofthese Specifications, the user is agreeing to the following terms of indemnity, warranty disclaimer, and disclaimer of liabilityo

The use of these Specifications is permissive, not mandatory. Voluntary use is within the control and discretion of the user andis not intended to, and does not in any way limit the ingenuity, responsibility or prerogative of individual manufacturers to designor produce electric overhead traveling cranes which do not comply with these Specifications. CMAA has no legal au1hority to requireor enforce compliance with these Specificationso These advisory Specifications provide technical guidelines for the user to specifyhis application. Following these Specifications does not assure his compliance with applicable federal, state, or local regulationsand codeso These Specifications are not binding on any person and do not have the effect of lawo

CMAA and MHI do not approve, rafe, or endorse these Specifications. They do not take any position regarding any patent rightsor copyrights which could be asserted with regard to these Specifications and do not undertake to ensure anyone using theseSpecifications against liability for infringement of any applicable Letters Patent. copyright liability, nor assume any such liabilityoUsers of these Specifications are expressly advised that determination 01 the validity 01 any such copyrights, patent rights, and the

risk of inlringement of such rights is entirely their own responsibilityo

DISCLAIMERS AND INDEMNITY

DISCLAIMER OF WARRANTY: CMAA AND MHI MAKE NO WARRANTlES WHATSOEVER IN CONNECTION WITH THESESPECIFICA TIONS. THEY SPECIFICALL y DISCLAIM ALL IMPLlED WARRANTIES OF MERCHANTABILlTY OR OF FITNf~ .

FOR PARTICULAR PURPOSE. NO WARRANTIES (EXPRESS, IMPLlED, OR STATUTORY) ARE MADE IN CONNECi.. .

WITH THESE SPECIFICA TIONS.

DISCLAIMER OF LlABILlTY: USER SPECIFICALL y UNDERST ANDS AND AGREES THA T CMAA, MHI, THEIR OFFICERS,AGENTS AND EMPLOYEES SHALL NOT BE LlABLE IN TORT AND IN CONTRACT -WHETHER BASED ON W ARRANTY ,NEGLlGENCE, STRICT LlABILlTY, OR ANY OTHER THEORY OF LlABILITY-FOR ANY ACTION OR FAILURE TO ACT INRESPECT TO THE DESIGN, ERECTION, INSTALLATION, MANUFACTURE, PREPARATION FOR SALE, SALE,CHARACTERISTICS, FEA TURES, OR DELlVERY OF ANYTHING COVERED BY THESE SPECIFICA TlONS. BY REFERRINGTO, OR OTHERWISE EMPLOYING, THESE SPECIFICATIONS, IT IS THE USER'S INTENT AND UNDERSTANDING TOABSOL VE AND PROTECT CMAA, MHI, THEIR SUCCESSORS, ASSIGNS, OFFICERS, AGENTS, AND EMPLOYEES FROM

ANY AND ALL TORT, CONTRACT, OR OTHER LlABILlTY.

INDEMNITY: BY REFERRING TO, OR OTHERWISE EMPLOYING. THESE SPECIFICATIONS, THE USER AGREES TODEFEND, PROTECT, INDEMNIFY, AND HOLD CMAA, MHI, THEIR SUCCESSORS, ASSIGNS, OFFICERS, AGENTS, ANDEMPLOYEES HARMLESS OF, FROM AND AGAINST ALL CLAIMS, LOSSES, EXPENSES, DAMAGES AND LIABILlTIES,DIRECT, INCIDENTAL OR CONSEQUENTIAL, ARISING FROM USE OF THESE SPECIFICATIONS INCLUDING LOSS OFPROFITS AND REASONABLE COUNSEL FEES, WHICH MA y ARISE OUT OF THE USE OR ALLEGED USE OF SUCHSPECIFICA TlONS, IT BEING THE INTENT OF THIS PROVISION AND OF THE USER TO ABSOL VE AND PROTECT CMAA,MHI, THEIR SUCCESSORS, ASSIGNS, OFFICERS. AGENTS, AND EMPLOYEES FROM ANY ANO ALL LOSS RELA TING IN

ANY WAY TO THESE SPECIFICATIONS INCLUDING THOSE RESULTING FROM THEIR OWN NEGLlGENCEo

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T ABlE OF CONTENTS

70-1 General Specifications 70-4 Mechanlcal Deslgn

1.1 Scope 4.1 Mean Effective Load1.2 Building Oesign Considerations 4.2 Load Blocks1.3 Clearance 4.3 Overload Limit Device1.4 Runway 4.4 Hoisting Ropes1.5 Runway Conductors 4.5 Sheaves1.6 Rated Capacity 4.6 Orum1.7 Oesign Stresses 4.7 Gearing1.8 General 4.8 Bearing1.9 Painting 4.9 Brakes1.10 Assemblyand Preparation for 4.10 Bridge Orives

Shipment 4.11 Shafting1.11 Testing 4.12 Couplings1.12 Orawings 4.13 Wheels1 .13 E rection 4.14 Bumpers1. 14 Lubrication 4.15 Stops1.15 Inspection. Maintenance and Crane

Operator.'~ 70-5 Electrical Equlpment

5.1 General70-2 Crane Classifications 5.2 Motors -AC and DC

2.1 General 5.3 Brakes2.2 Class A 5.4 Controllers, AC and DC2.3 Class B 5.5 Resistors2.4 Class C 5.6 Protective and Safety Features2.5 Class O 5.7 Master Switches2.6 Class E 5.8 Floor Operated Pendant Pushbutton2.7 Class F Stations2.8 Crane Service Class in Terms of Load 5.9 Limit Switch es

Class and Load Cycles 5.10 Installation5.11 Bridge Conductor Systems5.12 Runway Conductor Systems

70-3 Structural Design 5.13 Voltage Drop5.14 Inverters

3.1 Material 5.15 Remote Control3.2 Welding

r 3.3 Structure.'\.-, 3.4 Allowable Stresses 70-6 Inquiry Data Sheet and Speeds

3.5 Design Limitations3.6 Bridge End Truck3.7 Footwalks and Handrails 70-7 Glossary3.8 Operator's Cab3.9 Trolley Frames3.10 Bridge Rails 70-8 Index3.11 End Ties3.12 Bridge Trucks for 8. 12. and 16 Wheel

Cranes3L13 Structural Bolting3.14 Gantry Cranes

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70-1 GENERAL SPECIFICATIONS

1.1 SCOPE

1.1.1 This specification shall be known as the Specifications for T op Running Bridge & Gantry Type MultipleGirder Electric Overhead Traveling Cranes .CMM Specification No. 70 -Revised 2000.

1.1.2 The specifications and information contained in this publication apply to top running bridge and gantry itype multiple girder electric overhead traveling cranes. It should be understood that the specifications Iare general in nature and other specifications may be agreed upon between the purchaser and themanufacturer to suit each specific installation. These speclficatlons do not cover equlpment usedto lift, lower, or transpon personnel suspended from the holst rape systern.

1.1.3 This specification outlines in Section 70-2 six different classes of crane service as a guide for determiningthe service requirements of the individual application. In many cases there is no ctear category of servicein which a particular crane operatíon may fall, and the proper selectíon of a crane can be made onlythrough a discussion of service requirements and crane details with the crane manufacturer or other

qualified persons.

1.1.4 Service conditions have an important influence on the life ofthe wearing parts of a crane, such as wheels,gears, bearings, wire rape, electrical equipment, and must be considered in specifying a crane to assuremaximum life and minimum maintenance.

1.1.5 In selectíng overhead crane equipment, it is important that not only present but future operatíons(considered which may increase loading and service requirements and that equipment be selected whichwill satísfy future increased service conditíons, thereby minimizing the possibility of overloading orplacing in a duty classificatíon higher than intended.

1.1 .6 Parts of this specificatíon refer to certain portions of other applicable specifications, codes or standards.Where interpretatíons differ, CMAA recommends that this specification be used as the guideline.Mentíoned in the text are publicatíons of the following organizatíons:

ABMA American Bearing Manufacturers Association1200 12th Street, N.W. Suite 300Washington, DC 20036-2422

AGMA American Gear Manufacturers Assocíation1500 King Street, Suite 201

Alexandria, Virginia 22314

2001-C95- Fundamental Rating Factors and Calculation Methods lor Involute Spur and Helical Gear Teeth

AISC American Institute of Steel Construction ( -

1 East Wacker, Suite 3100 --Chicago, Illinois 60601-2001

ANSI American National Standards Institute11 West 42nd StreetNew York, New York 10036

ANSI/ASCE 7-95 -Minimum Design Loads for Buildings and Other StructuresANSI/ASME B30.2-1995 -Overhead & Gantry Cranes (Top Running Bridge, Single or Mulitiple Girder,

Top Running Trolley Hoist)

ASME The American Society of Mechanical Engineers--Three Park Avenue

New York, NY 10016-5990

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ASTM American Society for Testing & Materials1 00 Barr Harbor DriveWest Conshocken. Pennsylvania 19428

AWS American Welding Society550 N.W. LeJeune RoadMiami, Florida 33126

D14.1-97 -Specification for Welding of Industrial and Mili Cranes

CMAA Crane Manufacturers Association of America, Inc.8720 Red Oak Blvd., Surte 201Charlotte. North Carolina 28217-3992

Overhead Crane Inspection and Maintenance ChecklistCrane Operator's Manual

.Crane Operator's Training Video

NEC/ National Eiectrical CodeNFPA National Fire Protection Association

1 Batterymarch Park, P.O. Box 9101Quincy, Massachusetts 02269-9101

1999 70-935B

--NEMA National Electrical Manufacturers AssociationI\ ! 1300 North 17th Street, Suite 1847., Rosslyn, Virginia 22209

ICS1-1993 -Industrial Control Systems and Electrical Requirements

OS HA U.S. Department of LaborDirectorate of Safety Standards Programs200 Constitution Avenue. N.W.Washington, D.C. 20210

29 CFR Part 1910 -Occupational Safety & Health Standards for Generallooustry (Revised 7/1/97)

Stress Concentration FactorsR.E. Peterson/Walter D. PilkeyCopyright. 1997John Wiley & Sons. Inc.

Data was utilized from (FEM) Federation Europeenne De La Manutention, Section I Heavy Ufting Equipment, Rulesfor the Design of Hoisting Appliances. 3rd Edition -October 1987.

1.2 BUILDING DESIGN CONSIDERA TIONS, , i .2. 1 The building in which an overhead crane is to be installed must be designed with consideration given

"'- to the following points:

1.2.1.1 The distance from the floor to the lowest overhead obstruction must be such as to allow for the requiredhook lift plus the distance from the saddle or palm of the hook in its highest position to the high point onthe crane plus cJearance to the lowest overhead obstruction.

1.2.1.2 In addition, the distance from the floor to the lowest overhead obstruction must be such that the lowestpoint on the crane will clear all machinery or when necessary provide railroad or truck clearance underthe crane.

1.2.1.3 After determination of the building height, based on the factors above, the crane runway must be locatedwith the top of the runway rail at a distance below the lowest overhead obstruction equal to the heightof the crane plus clearance.

1.2.1.4 Lights, pipes, or any other objects projecting below the lowest point on the building truss must beconsidered in the determination of the lowest overhead obstruction.

1.2.1.5 The building knee braces must be designed to permit the required hook approaches.5

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1.2.1.6 Access to the cab or bridge walkway shou/d be a fixed ladder, stairs, or p/atfonT1 requiring no step over .

any gap exceeding 12 inches. Fixed ladders shall be in conformance with ANSI A 14.3, SafetyRequirements for Fixed Ladders.

1.3 CLEARANCE

1.3.1 A minimum clearance of 3 inches between the highest point of the crane and the lowest overhead

obstruction shall be provided. For buildings where truss sag becomes a factor, this clearance shouldbe increased.

1.3.2 The clearance between the end of the crane and the building columns, knee braces or any other

obstructions shall not be less than 2 inches with crane centered on runway rails. Pipes, conduits, etc.must not reduce this clearance.

1.4 RUNWAY

1.4.1 The crane runway, runway rails, and crane stops are typically fumished by the purchaser unless

otherwise specified. The crane stops fumished by the purchaser are to be designed to suit the specificcrane to be installed.

1.4.2 The runway rails shall be straight, parallel, level and at the same elevation. The distance, center lf

center, and the elevation shall be within the tolerances given in T able 1.4.2-1. The runway rails ShOll..,be standard rail sections or any other commercial rolled sections with equivalent specifications of aproper size for the crane to be installed and must be provided with proper raíl splices and hold-downfasteners. Aail separation at joint should not exceed 1/16 inch. Floating rails are not recommended.

1.4.3 The crane runway shall be designed with sufticient strength and rigidity to prevent detrimentallateral orvertical deflection.

The lateral deflection should not exceed L,/400 based on 10 percent of maximum wheelload(s) withoutV/F. The vertical deflection should not exceed L,/600 based on maximum wheelload(s) without VIF.Gantry and other types of special cranes may require additional considerations.

L, = Aunway girder span being evaluated.

1.5 RUNW A y CONDUCTORS

1.5.1 The runway conductors may be bare hard drawn copper wire, hard copper, aluminum or steel in the formof stiff shapes, insulated cables, cable reel pickup or other suitable means to meet the particularapplication and shall be installed in accordance with Article 610 of the National Electric Code and comrwith all applicable codeso \ ~

1.5.2 Contact conductors shall be guarded in a manner that persons cannot inadvertent/y touch energized

current-carrying parts. Flexible conductor systems shall be designed and installed in a manner tominimize the eftects of flexing, cable tension, and abrasion.

1.5.3 Runway conductors are normally furnished and installed by the purchaser unless otherwise specified.

1.5.4 The conductors shall be properly supported and aligned horizontally and vertically with the runway rail.

1.5.5 The conductors shall have sufticient ampacity to carry the required current to the crane, or cranes,whenoperating with rated loado The conductor ratings shall be selected in accordance with Article 610 of theNational Electrical Codeo For manufactured conductor systems with published ampacities, theintermittent ratings may be used. The ampacities of fixed loads such as heating, lighting, and airconditioning may be computed as 2.25 times their sum total which will permit the application of theintermittent ampacity ratings for use with continuous fixed loads.

1.5.6 The nominal runway conductor supply system voltage, actual input tap voltage, and runway conductorvoltage drops shall result in crane motor voltage tolerances per Section 5.13 (Voltage Drops).

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1.5.7 In a crane inquiry the runway conductor system type should be specified and jf !he system will besupplied by the purchaser or crane manufacturero If supplied by the purchaser, the kK:8tM>n should be .

stated.

1.6 RATED CAPACITY

1.6.1 The rated capacity of a crane bridge is specified by the manufacturero This capacity shall be markedon each side of the crane bridge and shall be legible from the operating floor.

1.6.2 Individual hoist units shall have their rated capacity marked on their bottom block. In addition, capacitylabel should be marked on the hoist body.

1.6.3 The totallifted load shall not exceed the rated capacity of the crane bridge. Load on individual hoist orhooks shall not exceed their rated capacity.

1.6.4 When determining the rated capacity of a crane, all accessories below the hook, such as load bars,magnets, grabs, etc., shall be included as part of the load to be handled.

1.7 DESIGN STRESSES

1.7.1 Materials shall be properly selected for the stresses and work cycles to which they are subjected.

,..Structural parts shall be designed according to the appropriate limits as per Chapter 70-3 of lspecification. Mechanical parts shall be designed according to Chapter 70-4 of this specification. AIIother load carrying parts shall be designed so that the calculated static stress in the material, based onrated crane capacity, shall not exceed 20 percent of the published average ultimate strength of thematerial.

This limitation of stress provides a margin of strength to allow for variations in the properties of materials,manufacturing and operating conditions, and design assumptions, and under no condition should implyauthorization or protection for users loading the crane beyond rated capacity.

1.8 GENERAL

1.8.1 AII apparatus covered by this specification shall be constructed in a thorough and workmanlike manner.Due regard shall be given in the design for operation, accessibility, interchangeability and durability of

parts.

1.8.2 This specification includes all applicable features of OS HA Section 1910. 179-Overhead and GantryCranes; and ANSI/ASME B30.2-Safety Standard for Overhead and Gantry Cranes.

.--'1.9 PAINTING (-

1.9.1 Before shipment, the crane shall be cleaned and given a protective coating.

1.9.2 The coating may consist of an number of coats of primer and finish paint according to the manufacturer'sstandard or as otherwise specified.

1.10 ASSEMBLV AND PREPARATION FOR SHIPMENT

1.10.1 The crane should be assembled in the manufacturer's plant according to the manufacturer's standard.When feasible, the trolley should be placed on the assembled crane bridge, but it is not required to reevethe hoisting rape.

1.10.2 AII parts of the crane should be carefully match-marked.

1.10.3 AII exposed finished parts and electrical equipment are to be protected for shipment. If storage isrequired, arrangements should be made with the manufacturer for extra protection.

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1.11 TESTlNG1.11.1 T esting in the manufacturer's plant is conducted according to the manufacturer's testing procedure,

unless otherwise specified.

1.11.2 Any documentation of non-destructive testing of material such as x-ray, ultrasonic, magnetic partide,etc. should be considered as an extra item and is normally done only if specified.

1.12 DRAWINGS

1.12.1 Normally two (2) copies of the manufacturer's clearance diagrams are submitted for approval, one ofwhich is approved and retumed to the crane manufacturero Also, two sets of operating instructions andspare parts information are typically fumished. Detail drawings are normally not fumished.

1.13 ERECTION

1.13.1 The crane erection (including assembly, field wiring, installation and starting) is normally agreed u~between the manufacturer and the owner or specifier. Supervision of field assembly and/or finalcheckout may algo be agreed upon separately between the manufacturer and the owner or specifier.

1.14 LUBRICATIONC ' 1.14.1 The crane shall be provided with all the necessary lubrication flttings. Before putting the crane in

operation, the erector of the crane shall assure that all bearings, gears, etc. are lubricated in accordancewith the crane manufacturer's recommendations.

1.15 INSPECTION, MAINTENANCE AND CRANE OPERATOR

1.15.1 For inspection and maintenance of cranes, refer to applicable section of ANSI/ASME B30.2, Chapter2-2, and CMAA-Overhead Crane Inspection and Maintenance Checklist.

1.15.2 For operator responsibility and training, refer lo applicable section of ANSI/ASME B30.2, Chapter 2-3,CMAA-Crane Operator's Training Video and CMAA-Crane Operator's Manual.

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70-2 CRANE CLASSIACA T10NS2.1 General

2.1.1 Service classes have been established so that the most economical crane for the installation may be specifiedin accordance with this specification.

The crane service classification is based on the load spectrum reflecting the actual service conditions asclosely as possible.

Load spectrum is a mean effective foad, which is unifonnly distributed over a probability scale and appliedto the equipment at a specified frequency. The selection of the properly sized crane component to perlorma given function is detennined by the varying load magnitudes and given load cycles which can be expressedin terms of the mean effective load factor.

k= ~ (W,)3P 1 + (WJ3p 2 + (W3)3P 3 + ...(Wn)3P n

Where W = Load magnitude; expressed as a ratio of each lifted load to the rated capacity. Operation with

no lifted load and the weight of any attachment must be included.

P = Load probability; expressed as a ratio of cycles under each load magnitude condition to the total

cycles. The sum total of the load probabilities P must equal 1.0.

k = Mean effective load factor. (Used to establish crane service class only) ;""

AII classes of cranes are affected by the operating conditions, therefore for the purpose of the classificati~S,it is assumed that the crane will be operating in normal ambienttemperature O" to 104"F (-17.8" to 40"C) andnormal atmospheric conditions (free from excessive dust, moisture and corrosive fumes).

The cranes can be classified into loading groups according to the service conditions of the most severely loadedpart of the crane. The individual parts which are clear1y separate from the rest, or fonning a self containedstructural unit, can be classified into different loading groups if the service conditions are fully known.

2.2 CLASS A (STANDBY OR INFREQUENT SERVICE)

This service class covers cranes which may be used in installations such as powerhouses, public utilities,turbine rooms, motor rooms and transformer stations where precise handling of equipment at slow speedswith long, idle periods between lifts are required. Capacity loads may be handled for initial installation ofequipment and for infrequent maintenance.

2.3 CLASS B (LlGHT SERVICE)

This service covers cranes which may be used in repair shops, light assembly operations, service buildinr-c;.light warehousing, etc., where service requirements are light and the speed is slow. Loads may vary fro"load to occasional full rated loads with two to five lifts per hour, averaging ten feet per lift.

2.4 CLASS C (MODERA TE SERVICE)

This service covers cranes which may be used in machine shops or papermill machine rooms, etc., whereservice requirements are moderate. In this type of service the crane will handle loads which average 50percent of the rated capacity with 5 to 10 lifts per hour, averaging 15 feet, not over 50 percent of the lift at ratedcapacity .

2.5 CLASS D (HEA VY SERVICE) -

This service covers cranes which may be used in heavy machine shops, foundries. fabricating plants, steelwarehouses, container yards, lumber milis, etc., and standard duty bucket and magnet operations whereheavy duty production is required. In this type of service, loads approaching 50 percent of the rated capacitywill be handled constantly during the working periodo High speeds are desirable for this type of service with10 to 20 lifts per hour averaging 15 feet, not over 65 percent of the lifts at rated capacity.

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I 2.6 CLASS E (SEVERE SERVlCE) ~

This type of service requires a crane capable of handling loads approaching a rated capacity throi4X>Ut itslife. Applications may include magnet, bucket, magnet'bucket combination cranes for scrap yards, cementmilis, lumber milis, fertilizer plants, container handling, etc., with twenty or more lifts per hour at or ~r the

rated capacity.

2.7 CLASS F (CONTINUOUS SEVERE SERVICE)

This type of service requires a crane capable of handling loads approaching rated capacity continuouslyunder severe service conditions throughout its life. Applications may include custom designed specialtycranes essential to performing the critical work tasks affecting the total production facility. These cranesmust provide the highest reliability with special attention to ease of maintenance features.

2.8 CRANE SERVICE CLASS IN TERMS OF LOAO CLASS ANO LOAO CYCLES

The definition of CMAA crane service class in terms of load class and load cycles is shown in TabIe2.8-1.

TABLE 2.8-1OEFINITION OF CMAA CRANE SERVICE CLASSIN TERMS OF LOA O CLASS ANO LOAO CYCLES

Load cles k -MEANLOAD EFFECTIVECLASS N, Na N3 N. LOAD

FACTOR

L, A B C D 0.35 -0.53La B C D E 0.531-0.67L., C D E F 0.671-0.85L,. D E F F 0.851-1.00

Irregularoccasional Regular Regular Regular useuse use in use in in severe

followed by Intermittent contlnuous continuouslong idle operation operation operation

periods

LOAD CLASSES:

.,1 = Cranes which hoist the rated load exceptionally and, normally, very light loads.

L2 = Cranes which rarely hoist the rated load, and normalloads of about 1/3 of the rated loado

L3 = Cranes which hoist the rated load fairly frequently and normally, loads between 1/3 and 2/3 of the rated

loado

~ = Cranes which are regularly loaded clase to the rated loado

LOAD CYCLES:

N, = 20,000 to 100,000 cyclesN2 = 100,000 to 500,000 cyclesN3 = 500,000 to 2,000,000 cyclesN4 = Over 2,000,000 cycles

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70-3 STRUCTURAL DESIGN

3.1 MATERIAL

3.1.1 AII structural steel used should conform to ASTM-A36 specifications or shall be an accepted type for thepurpose for which the steel is to be used and for the operations to be performed on it. Other suitablematerials may be used provided that the parts are proportioned to comparable design factors.

3.2 WELDING

3.2.1 AII welding designs and procedures shall conform to the current issue of A WS 014.1, 'Specification forWelding Industrial and Mili Cranes." Weld stresses determined by load combination case 1, Sections3.3.2.4.1 and 3.4.4.2, shall not exceed that shown in the applicable Section 3.4.1 or Table 3.4.7-1.Allowable weld stress es for load combination cases 2 and 3, Sections 3.3.2.4.2 and 3.3.2.4.3, are to beproportioned in accordance with Sections 3.4.2 and 3.4.3.

3.3 STRUCTURE

3.3.1 General

The crane girders shall be welded structural steel box sections, wide flange beams, standard I-beams,reinforced beams or sections fabricated from structural plates and shapes. The manufacturer shallspecify the type and the construction to be fumished. Camber and sweep should be measured by ~manufacturer prior to shipment.

3.3.2 Loadings

The crane structures are subjected, in service, to repeated loading varying with time which inducevariable stresses in members and connections through the interaction of the structural system and thecross-sectional shapes. The loads acting on the structure are divided into three different categories. AIIof the loads having an influence on engineering strength analysis are regarded as principal loads,namely the dead loads, which are always present; the hoist load, acting during each cycle; and the inertiaforces acting during the movements of cranes, crane componen.ts, and hoist loads. Load effects, suchas operating wind loads, skewing forces, snow loads, temperature effect, loads on walkways, stairways,platforms and handrails are classed as additionalloads and are only considered for the general strengthanalysis and in stability analysis. Other loads such as collision, out of service wind loads, and test loadsapplied during the load test are regarded as extraordinary loads and except for collision and out ofservice wind loads are not part of the specification. Seismic forces are not considered in this designspecification. However, if required, accelerations shall be specified at the crane rail elevation by theowner or specifier. The allowable stress levels under this condition of loading shall be agreed upon withthe crane manufacturero ,

\3.3.2.1.1 Principal Loads

3.3.2.1.1.1 Dead Load (DL)

The weight of sIl effective parts of the bridge structure, the machinery parts and the fixed equipmentsupported by the structure.

3.3.2.1.1.2 Trolley Load (TL)

The weight of the trolley and the equipment attached to the trolley.

3.3.2.1.1.3 Lifted Load (LL)

The lifted load consists of the working load and the weight of the lifting devices used for handling andholding the warning load such as the load block, lifting beam, bucket, magnet, grab and othersupplemental devices.

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3.3.2.1.1.4 Vertical lnertia Forces (VIF)

The vertical inertia forces include those due to the motion of the cranes or crane components and thosedue to lifting or lowering of the hoist loado These additional loadings may be included in a simplifiedmanner by the application of a separate factor for the dead load (DLF) and for the hoist load (HLF) bywhich the vertical acting loads, the member forces or the stress es due to them, must be multiplied.

3.3.2.1.1.4.1 Dead Load Factor (DlF)

This factor covers only the dead loads of the crane. trolley and its associated equipment and shall betaken according to:

Travel Speed (FPM)DLF = 1.1 :5: 1.05 + :5: 1.2

2000

3.3.2.1.1.4.2 Hoist load Factor (HlF)

This factor applies to the motion of the rated load in the vertical direction, and covers inertia forces. themass forres due to the sudden lifting of the hoist load and the uncertainties in allowing for otherinfluences. The hoist load factor is 0.5 percent of the hoisting speed in feet par minute, but not less than15 percent or more than 50 percent, except for bucket and magnet cranes for which the value shall be

,,- taken as 50 percent of the rated capacity of the bucket or magnet hoist.

(. HLF = .15:5: .005 x Hoist Speed (FPM):5:.5

3.3.2.1.1.5 Inertia Forces From Drives (IFD)

The inertia forces occur during acceleration or deceleration of crane motions and depend on the drivingand braking torques applied by the drive units and brakes during each cycle.

The lateral k>ad due to acceleration or deceleration shall be a percentage of the verticalload and shallbe considered as 7.8 times the acceleration or deceleration rafe (FT/SEC2) but not les s than 2.5 percentof the vertical loado This percentage shall be applied to both the live and dead loads, exclusive of theendtrucks and end tieso The live load shall be located in the sama position as when calculating the verticalmomento The lateralload shall be equally divided between the two girders. and the moment 01 inertia01 the entire girder section about its vertical axis shall be used to determine the stresses due to lateralforces. The inertia forces during acceleration and deceleration shall be calculated in each case with thetrolley in the worst position for the component being analyzed.

3.3.2.1.2 Additional Loads:

3.3.2.1.2.1 Operating Wind load (WLO)

Unless otherwise specified. the lateral operational load due to wind on outdoor cranes shall beconsidered as 5 pounds per square foot of projected area exposed to the wind. The wind load on thetrolley shall be considered as equally divided between the two girders. Where multiple surfaces areexposed to the wind, such as bridge girders, where the horizontal distance between the surfaces isgreaterthan the depth ofthe girder, the wind area shall be considered to be 1.6 times the projected area01 the larger girder. For single surfaces. such as cabs or machinery enclosures, the wind area shall beconsidered to be 1.2 (or that applicable shape factor specified by ASCE 7 -Iatest revision) times theprojected area to account for negative pressure on the leeward side of the structure.

,~

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3.3.2.1.2.2 Forces Due to Skewlng (SK)

When two wheels (or two bogies) roll along a rail, the horizontal forces normal to the raíl, andtending to skew the structure shall be taken into consideration. The horizontal forces shall be obtainedby multiplying the verticalIDad exerted on each wheel (or bogie) by coefficient S'k which depends uponthe ratio 01 the span to the wheel base.

0.15

Su 0.10

0.05

3 4 5 6 7

RATIO -SPANWHEELBASE

3.3.2.1.3 Extraordinary Loads: f p ~.3.3.2.1.3.1 Sto red Wlnd Load (WLS) )ii

This is the maximum wind that a crane is designed to withstand during out of service condition. Thespeed and test pressure varíes with the height of the crane above the surrounding ground leve',geographicallocation and degree of exposure to prevailing winds (See ASCE 7 -Iatest revision as applicable).

3.3.2.1.3.2 Colllslon Forces (CF)

Specialloading 01 the crane structure resulting Irom the bumper stops, shall be calculated with the craneat 0.4 times the rated speed assuming the bumper system is capable of absorbing the energy within itsdesign stroke. Load suspended from lifting equipment and free oscillating load need not be taken intoconsideration. Where the load cannot swing, the bumper effect shall be calculated in the same manner,taking into account the value of the loado The kinetic energy released on the collision of two cranes withthe moving masses of M" M2' and a 40 percent maximum traveling speed 01 V T, and V T2 shall bedetennined from the 101l0wing equation:

M,M2 (.4VT1 + .4VT2)2E=

2(M + M) "",", 2 r

The bumper forces shall be distributed in accordance with the bumper characteristics and the freedomof the motion of the structure with the trolley in its worst position.

3.3.2.2 Torslonal Forces and Moments

3.3.2.2.1 Due to the Startlng and Stopplng of the Bridge Motors:

The twisting moment due to the starting and stopping of bridge motors shall be considerad as the startingtorque of the bridge motor at 200 percent of fullload torque multiplied by the gear ratio between the motorand cross shaft.

3.3.2.2.2 Due to Vertical Loads:

3.3.2.2.2.1 Torsional moment due to vertical forces acting eccentric to the vertical neutral axis 01 the girder shall beconsidered as those vertical forces multiplied by the horizontal distance between the centerline of theforces and the shear center 01 the girder.

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3.3.2.2.3 Due to Lateral Loads:

3.3.2.2.3.1 The torsional moment due to the lateral forces acting eccentric to the horizontal neutral axis of the girdershall be considered as those horizontal forces multiplied by the vertical distance between the centerlineof the forces and the shear center of the girder.

3.3.2.3 Longitudinal Distrlbutlon 01 the Wheel Load

Local stresses in the rail, rail base, flanges, welds, and in the web plate due to wheelload acting normaland transversely to the rail shall be determined in accordance with the rail and flange system. Theindividual wheelload can be uni10rmly distributed in the direction 01 the rail over a length 01 S = 2(R +C) + 2 in., provided that the rail is directly supported on the flange as shown in Figure 3.3.2.3-1.

~~.I f ../' where H = R + C

I E R S = 2H + 2 in. = 2(R + C) + 2 in.

1,~~ I I -~ C R = heightoftherail\ 450 450 v I

..I sic = thickness of top cover plate

1---1 II

Fig. 3.3.2.3-1

3.3.2.4 Load Combinatlon

The combined stresses shall be calculated for the following design cases:

3.3.2.4.1 Case 1: Crane in regular use under principalloading (Stress Level1)

DL(DLF s> + TL(DLF T) + LL( 1 + HLF) + IFD

3.3.2.4.2 Case 2: Crane in regular use under principal and additionaJ loading (Stress Level 2)

DL(DLF s> + TL(DLF T) + LL(1 + HLF) + IFD + WLO + SK

J.3.2.4.3 Case 3: Extraordinary loads (Stress Level 3)

3.3.2.4.3.1 Crane subjected to out of service wind

DL + TL + WLS

3.3.2.4.3.2 Crane in collision

DL + TL + LL + CF

3.3.2.4.3.3 Test Loads

CMAA recommends test load not to exceed 125 percent of rated loado

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3.4 ALLOWABLE STRESSES

STRESS ALLOWABLE ALLOWABLE ALLOWABLE ALLOWABLELEVEL COMPRESSION TENSION SHEAR BEARING

ANDCASE STRESS. STRESS STRESS STRESS

3.4.1 1 O.600yp O.600yp O.350yp O.75Oyp

3.4.2 2 O.660yp O.660yp O.3750yp O.800yp

3.4.3 3 O.750yp O.750yp O.430yp O.9OOyP

*Not subject to buckllng. "Se8 paragraph 3.4.6 and 3.4.8"

3.4.4 Combined Stresses

3.4.4.1 Where state of combined plane stress es exist, the reference stress O" can be calculated from theI

101l0wing formula:

O" = V(0)2 + (0".)2 -0"0" + 3(17)2 oS O"I .Y .y xy All. C~

3.4.4.2 For welds, maximum combined stress O"V shall be calculated as follows:

Oy = [O. + O"~ :t i\/(O". -Oy)2 + 4(~)2 oS O"ALL.

3.4.5 Buckling Analysls

The analysis for proving safety against local buckling and lateral and torsional buckling of the web plateand local buckling of the rectangular plates forming part 01 the compression member, shall be made inaccordance with a generally accepted theory of the strength of materials. (See Section 3.4.8)

3.4.6 Compresslon Member

3.4.6.1 The average allowable compression stress on the cross section afea 01 axially loaded compressionmembers susceptible to buckling shall be calculated when KUr (the largest effective sJenderness ratio01 any segment) is less than Cc: ,r-

\

[1 -(KUr)2 J OO A = L .2 (CC)2 J yP

[ .5. + 3 (KUr) -(KUr)3 J N3 8Cc ~c;;r

where: Cc = V-- ~

O"yp

~c~' ¡: i

3.4.6.2 On the cross section 01 axially loaded compression members susceptible to buckling shall be calculatedwhen KUr exceeds Cc:

121r2EO A = 23(KUr)2 N

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Page 18: CMAA 70

3.4.6.3 Members subjected to both axial compression and bending stresses shall be proportioned to satisfy the

following requirements:

(J' C(J' C(J'--!- + mx bx + -rny -by s 1.0

(J'A [1 -~ ] (J'BX [1 -~] (J'BY

.x ex

(J'. (J'bx (J'bv 1O-+ -+ ---="'- s(J'BK (J'BX (J'BY .

(J'.when cr s .15 the following formula may be used

A

(J' (J' (J'--L + ~ + ~ s 1.0(J'A (J'BX (J'BY

where:K = effective length factorL = unbraced length of compression member

., r = radius of gyration of member(7 E = modulus of elasticity",. (J' = yield point

yp(J'. = !he computed axial stress(J'b = computed compressive bending stress at the point under

consideration(J' A = axial stress that will be permitted if axial force alone existed(J'B = compressive bending stress that will be permitted if bending

moment afane existed(J'BK = allowable compression stress from Section 3.4(J' = 127t2E.

23(KUr)2 NN = 1.1 Case 1N = 1.0 Case 2N = 0.89 Case 3

C and C = a coefficient whose value is taken to be:mx my

1. For compression members in trames subject to joint translation (sidesway), Cm = 0.85

2. For restrained compression members in trames braced against joint transJation and not\, subject to transverse foading between their supports in !he plane of bending,

Cm = 0.6 -0.4 ~ ,but not less than 0.4

M2

where M,/M2 is the ratio of the smallerto larger moments at the ends of that portion of the memberunbraced in the plane of bending under consideration. M,/M2 is positive when the member is bentin reverse curvature, negative when bent in single curvature.

3. For compression members in trame braced against joint translation in the plane of loadingand subjected to transverse foading between their supports, the value 01 Cm may be de-termined by rational analysis. However, in fieu of such analysis, the following values maybe used:

a. For members whose ends are restrained C = 0.85m

b. For members whose ends are unrestrained C = 1.0m

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Page 19: CMAA 70

3.4.7 Allowable Stress Range -Repeated LOId

Members and fasteners subject to repeated load shall be designed so that the maximum stress doesnot exceed that shown in Sections 3.4.1 thru 3.4.6, nor shall the stress range (maximum stress minusminimum stress) exceed allowable values forvarious categories as listedin Table 3.4.7-1. The minimumstress is considered to be negative if it is opposite in sign to the maximum stress. The categories aredescribed in Table 3.4.7-2A with sketches shown in Figure 3.4.7-28. The allowable stress range is tobe based on the condition most nearly approximated by the description and sketch. See Figure 3.4.7-3 for typical box girders. See Figure 3.4.7-4 for typical bridge rail.

TABLE 3.4.7-1

ALLOWABLE STRESS RANGE -ksl

CMAA Jolnt CategoryServlceClass A B C D E F

A 63 49 35 28 22 15

B 50 39 28 22 18 14 {-

C 37 29 21 16 13 12

D 31 24 17 13 11 11 i.

E 24 18 13 10 8 9 f-:

F 24 16 10 7 5 8

Stress range values are independent of material yleld stress.

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FIGURE 3.4.7-28 ;"

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Page 24: CMAA 70

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FIGURE NO. 3.4.7-4FOR TYPICAL BRIDGE RAIL

.

-~-<M6N 0

C~.4.8 Buckllng.3.4.8.1 Local Buckling or Crlppllng 01 Flat Plates

The structural design of the crane must guard against local buckling and lateral torsional buckling of the

web plates and cover plates of girder. For purposes of assessing buckling, the plates are subdividedinto rectangular panels of length "a" and width obR. The length "a" of these panels corresponds to the

center distance of the full depth diaphragms or transverse stiffeners welded to the panels.

In the caese of compression flanges, the length "b" of the panel indicates the distance between webplates, or the distance between web plates and/or longitudinal stiffeners. In the case of web plates, thelength 01 "b" of the panel indicates the depth of the girder, or the distance between compression or

tension flanges and/or horizontal stiffeners.

23

Page 25: CMAA 70

3.4.8.2 Critical buckling stress shall be assumed to be a multiple of the Euler Stress (J.(J k = Ko CJ. ; ~ = K'T (J.

where: Ko = buckling coefficient compressionK'T = buckling coefficient shear

The buckling coefficient Koand K'Tare identified for a few simple cases for plates with simply supportededges in Table 3.4.8.2-1 and depend on:

-ratio a = a/b of the two sides of the plate.

-manner in which the plate is supported along the edges

-type of loading sustained by the plate.l

It is not the intention of this specification to enter into further details of this problem. For a more detailedand complex analysis such as evaluation of elastically restrained edges, continuity of plate, anddetermination of the coefficient of restraint, reference should be made to specialized literature.

CJ. = Euler buckling stress which can be determinad from the following formula:

2 2 2 (7t E t 6 t iCJ.- 12(1-Jl2)[b] -26.21 x 10 [b]

Where: E = modulus of elasticity (for steel E = 29,000,000 psi)

Jl = Poisson's ratio (for steel ~ = 0.3)

t = thickness of plate (in inches)

b = width of plate (in inches) perpendicular to the compression force

If compression and shear stresses occur simultaneously I the individual critical buckling stresses a k and'tk and the calculated stress values a and 't are used to determine the critical comparison stress:

'/02 + 3T2O1k. [ 1 + If' ][ Q ] + V [1--;-!- ~ 12 + r ¡ 1 23 -If' Q ] 2 + [.!.] 2

4 Ok 4 Ok Tk fwhere:

a = actual compression stress't = actual shear stressak = critical compression stress'tk = critical shear stress'JI = stress ratio (see Table No. 3.4.8.2-1)

In the special case where 't = O it is simply (J 1k = a k and in the special case where a = O then(J1k = 'tk~11 the resulting critical stress is below the proportional limit, buckling is said to be elastic. If the resultingvalue is above the proportionallimit, buckling is said to be inelastic. For inelastic buckling, the criticalstress shall be reduced to:

2CJyp (a,k)

O"'kR= 0.1836 (ayp)2+ (a,k)2

where: a = yield pointyp

ap = proportionallimit (assumed at ayp/1.32)

24

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Page 27: CMAA 70

~

3.4.8.3 Deslgn FactorsP- The buckling safety factor is ~ B calculated with the aid of the formula's: .

(J'kIn the case of elastic buckling: ~B=V(J2 + 3't2 ~ DFB

(J,kAIn the case of inelastic buckling: ~ B = V(J2 + 3't2 ~ DFB

The design factor DFB requirements of buckling are as follows:

TABLE 3.4.8.3-1

LOAD COMBINATION DESIGN FACTOR DFB

Case 1 1.7 + 0.175 ('1' -1)

Case 2 1.5 + 0.125 ('1' -1)

Case 3 1.35 + 0.05 ('1' -1) '-

3.5 DESIGN LIMITATIONS

3.5.1 Guideline for proportions of welded box girders:

Proportions:

Uh should not exceed 25Ub should not exceed 65

bit and hit to be substantiated by buckling analysis.

where:

L = span (inches)b = distance between webplates (inches)h = depth of girder (inches)t = thickness of plate (inches) ("

"-

~

26.-

~ '

Page 28: CMAA 70
Page 29: CMAA 70

3.5.3.3 For two longitudinal stiffeners at the third points of the compression flange, where ~ is the unsupportedwidth, the moment of inertia 0# each 0# the ~ stiffeners shall be no less than:

[ Aa ]-.E.. ~2 -!- 3lo -0.4 b + 0.8 [b] + 8.0 b2t bt

The moment 01 inertia need not be greater in any case than:

I = [9 + 56 ~ + 90 [~]2 ]bt3o bt bt

3.5.3.4 For three longitudinal stiffeners, spaced equidistant at the one 10urth width locations where b/4 is theunsupported width, and limited to a/b<3, the moment 0# inertia 0# each 01 the three stiffeners shall beno less than:

'o = [0.35 ~ + 1.10 [~]2 + 12 * ]bf3-in4

where:

a = longitudinal distance between diaphragms or transverse stiffeners (inches)

A. = afea 01 the stiffener (in2)

t = thickness 0# the stiffened plate (inches)

'o = moment 01 inertia (in4)

Stiffeners shall be designed to the provisions 01 Section 3.5.2.3. fit'

3.5.4 Dlaphragms and Vertical Stiffeners

3.5.4.1 The spacing 01 the vertical web stiffeners in inches shall not exceed the amount given by the 10rmula:

a= 350t

~-where: a = longitudinal distance between diaphragms or transverse stiffeners (inches)

t = thickness 01 web (inches)

'ty= shear stress in web plates (ksi)

Nor should the spacing exceed 72 inches or h, the depth 01 the web, whichever is greater.

3.5.4.2 Full depth diaphragms may be included as vertical web stiffeners toward meeting this requiremer

3.5.4.3 The moment 01 inertia 0# any transverse stiffener about the interface 01 the web plate, if used in theabsence 01 diaphragms, shall be no less than:

I = 1 .2 h3 (to)3

(ao)2

where: ao = required distance between stiffeners (inches)

to = minimum required web thickness (inches)

~I = moment 01 inertia (in4)

This moment 01 inertia does not include additional requirements, i1 any, 10r local moments. Stiffenerelements shall be proportioned to the provisions 01 Section 3.5.2.3.

28

.~

Page 30: CMAA 70

.

3.5.4.5 AII diaphragms shall bear against the top coyer plata and !hal be weIded fa the web platas. Thethickness of the diaphragm plata shaH be sufficient to resist the troIey wheel load in bearing at theallowable bearing stress on the assumption that the wheelload is distributed over a distance equaJ tothe width 01 the rail base plus twice the distance 1rom the rail base fa the top of the diaphragm plate.

3.5.4.6 Short diaphragms shall be placed between full depth diaphragms so that the maximum distancebetween adjacent diaphragms willlimit the maximum bending stress in the trolley rail without VIF forcesto 18 ksi for 'oad combination Case 1, Section 3.3.2.4.1 based on:

(trolle~ wheelload) (distance between dia~hragms) <18 ksi6 (section modulus of rail) -

maximum = 19.8 ksi for Case 2 and 22.5 ksi for Case 3

3.5.5 Deflection and Camber

3.5.5.1 The maximum vertical deflection of the girder produced by the weight of the hoist, trolley and the ratedload shall not exceed 1/88801 the span. Vertical inertia forces shall not be considered in determiningdeflection.

3.5.5.2 Box girders should be cambered an amount equal to the dead load deflection plus one-ha/f of the liveload deflection.

C. 3.5.6 Welded Torsion Box Glrders

3.5.6.1 Torsion girders, with the bridge rail over one web plata, are to be designed with the trolley wheelloadassumed to be distributed over a distance of the web plate as indicated in Section 3.3.2.3.

3.5.6.2 For box girders having compression flange areas no more than 50 percent greater than that of thetension flange, and with no more that 50 percent difference between the Breas 01 the two webs, the shearcenter may be assumed to be at the centroidal axis 01 the cross section.

3.5.7 Single Web Girders

Single web girders include wide flange beams, standard I beams, or beams rein10rced with plate, or otherstructural configurations having a single web. Where necessary, an auxiliary girder or other suitablemeans should be provided to support overhanging loads to prevent undue torsional and lateraldeflections.

The maximum stresses with combined loading for Case 1 shall not exceed:

,. Tension (net section) = 0.6 Oypc

;r' Compression (ksi) = 12,000 with maximum 01 0.6 OLd yp

Al

For cases 2 and 3, proportion stresses in accordance with Sections 3.4.1, 2 and 3.

where: L = span (unbraced fength 01 top flange) (inches)

Al = area 01 compression flange (in2)

d = depth 01 beam (inches)

Shear = 0.35 Oyp

Box Section Girders Bullt of Two Beams

Box section girders built up 01 two beams, either with or without reinforcing flange platas, shall bedesigned according to the same design data as for box section girder cranes for stress and deflection

values only.

29

Page 31: CMAA 70

,.

3.6 BRIDGE END TRUCK

3.6.1 The crane bridge shall be carried on end trucks designed to carry the rated load when lifted at one endof the crane bridge. The wheel base of the end truck shall be 1/7 of the span or greater.

3.6.2 End trucks may be of the rotating axle or fixed axle type as specified by the crane manufacturero

3.6.3 The bridge end trucks should be constructed of structural steel or other suitable material. Provision shallbe made to prevent the end truck from dropping more than one inch in case of axle failure. Guards shallbe provided in front of each outside wheel and shall project below the top of the runway raíl. Loadcombinations and basic allowable stresses are to be in accordance with Sections 3.3.2.4 and 3.4.

3.7 FOOTWALKS AND HANDRAILS

When specified, a footwalk with a handrail should be provided. The handrail shall be at least 42 incheshigh and provided with an intermediate railing. Footwalk shall have a slip-resistant walking surface andshall be protected on all exposed edges by a suitable roe guardo AII footwalks shall be designed for alive load of 50 pounds per square foot. For allowable stresses, use stress level 2, Section 3.4.2.

3.8 OPERA TOR'S CAB

3.8.1 The standard location of the operator's cab is at one end of the crane bridge on the driving girder sideunless otherwise specified. It shall be so located as not to interfere with the hook approach.

CThe operator's cab shall be open type for indoor service unless otherwise specified. The cab sha ..~adequately braced to prevent swaying or vibration, but not so as to interfere with access to the cab orthe vis ion of the operator. AII bolts for supporting member connections should be in shear. Cab shall beprovided with an audible warning device and tire extinguisher.

3.8.2 Provision shall be made in the operator's cab for placement of the necessary equipment, wiring andfittings. AII cabs should be provided with a seat unless otherwise specified.

3.8.3 For allowable stresses, use stress level 2, Section 3.4.2.

3.8.4 The controllers or their operating handles are located as shown in Section 5.7 for the cab location, unlessotherwise specified.

3.8.5 Means of access and egress from cab should comply with ANSI B30.2.

3.9 TROLLEY FRAMES

3.9.1 The trolley trame shall be constructed of structural steel and shall be designed to transmit the load tothe bridge rails without deflection which will impair functional operation of machinery. (,

3.9.2 Provision should be made to prevent a drop of more than one inch in case of axle failure.

3.9.3 Load combinations and allowable stresses are to be as specified in Sections 3.3.2.4 and 3.4.

3.10 BRIDGE RAILS

3.10.1 AII bridge rails shall be of first quality and conform to all requirements set forth in the specifications ofthe ASCE, ARA, AREA or any other commercial roIled sections with equivalent specifications.

3.10.2 Bridge rails shall be joined by standard joint bars or welded. The ends of non-welded sections shall besquare and sections joined without opening between ends. Provision shall be made to prevent creepingof the bridge rails.

3.10.3 Bridge rails shall be securely fastened in place to maintain center distance of rails.

3.10.4 Bridge and runway rails should be in accordance with Table 4.13.3-4 and consistent with the wheel

diameter and the maximum wheelload.

30

-

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Page 32: CMAA 70

,

3.11 ENDTlES --

End ties are to be provided between girders when deemed necessary tor stability ot the girders. to assistin squaring the crane. to participate with the girders in continuous trame action to resist horizootalloads,and to accommodate unbalanced torsional loads on the girders. When equalizer bridge trucks areincorporated in the crane design, the end ties shall be ot rigid construction and ot adequate strength toresist all ot the above loads. Flexiblity ot the end tie is necessary when equalizing provisions are notemployed. Due consideration should be given to the various types of loading conditions and the resulting ,",j"tstresses, which shall not exceed the values as stated in Section 3.4. '~'#',,:::

3.12 BRIDGE TRUCKS FOR 8,12 AND 16 WHEEL CRANES C

3.12.1 When appropriate, equalizer bridge trucks are to be incorporated to promote sharing of bridge wheelloads. Equalizing pins are to be provided between equalizer truck and equalizer beams and/or rigid

bridge structures.

3.12.2 For typical arrangement ot 8, 12 and 16 wheel cranes, see Figure 3.12.2-1.

16-WHEEL EOUALlZING

~~~==:::==::==~~~-8-WHEEL COMPENSATING ,~

16-WHEEL COMPENSATING

FIGURE 3.12.2-131

c.,\t!l"" '"

~~:-.:;:"'~

¡)(Crtt~'~;:

Page 33: CMAA 70

3.13 STRUCTURAL BOL TING

3.13.1 Joints designed as high strength bolted conncections are to conform to the requirements of the"Specification for Structural Joints Using ASTM A325 or A490 Bolts," as published by the AISC, for loadcombination, Case 1, Section 3.3.2.4.1. Zinc causes stress corrosion in A490 and should not be used.

3.13.2 Finished and unfinished bolts, ASTM A30?, are to be used at values of 90 percent of those tabulatedin Part 4 of the current issue of the AISC Manualof Steel Construction for load combination, Case 1,Section 3.3.2.4.1 .

3.13.3 Allowable bolt stresses for load combination Cases 2 and 3, Sections 3.3.2.4.2 and 3, are to beproportioned in accordance with Sections 3.4.12 and 3.

3.14 GANTRY CRANES

Design of leg, end tie, strut, and si" members shall conform to applicable sections of this specification.

C,

r..

;PU:C¡"';'" .,.C".,.

32

Page 34: CMAA 70

70-4 MECHANICAL DESIGN

4.1 MEAN EFFECTIVE LOAD

Note: In arder to facilitate a measure of durability ,Ioad and service factors shall be used to determine the mea neffective load in a service classifK::ation for mechanical components.

4.1.1 The mechanical mean effective Ioad factor Kw shall be established by the use of the fo/lowing basicformula.

Kw = 2(maximum load) + (minimum load)

3(maximum load)

The maximum load used in the above formula shall be established by using the rated load and applicabledead loads, so positioned as to result in the maximum reaction on the component under consideration.V/F shall not be included. The minimum load to be used shall be established by the dead load of thebridge and or trolley only.

4.1.2 Load factors ~ convert maximum k)ads into mean effective loads as follows, and are to be usad for geardurability horsepower and bearing life calculations.

Mean effective load = Maximum load x K.,

'1. 4.1.2.1 The load factor ~ for the hoist madlinery is established by the following formula:

Kwh = 2(rated k)ad) + 3(lower block weight)

3(rated load + lower block weight)

Lower blocks weighing less than 2 percent of rated capacity may be ignored resulting in K,... = .667.

4.1.2.2 The load factor Kwt for the trolley drive machinery is established by the following formula:

Kwt = 2(rated load) + 3(trolley weight)

3(rated load + trolley weight)

4.1.2.3 The load factor KWb for the bridge drive machinery is established by the following formula:

Kwb = 2(rated load) + 3(trolley weight + bridge weight)

3(rated k)ad + trolley weight + bridge weight)

4.1.2.4 For Kw factors of trolley and bridge wheel assemblies and axle bearing selection, see Section 4.13.3.

4.1.3 The machine service factor Cd listed in rabie 4. 1.3-1 depends on the class of crane service and accountsfor expected differences of load spectrum density and severity of service and is usad to determine gear

durability horsepower.4.1.4 Stress concentration factors can be obtained from data in stress concentration factors by R. E. Peterson

(see Section 1.1.6).

TABLE 4.1.3-1

Machlnery Servlce Factor Cd -""-

Clas~ of A B C O E FServlce

C .64 .72 .8 .9 1.0 1.16d

33

k. 8.

Page 35: CMAA 70

4.2 LOAD BLOCKS

4.2.1 The load block trame should be of steel construction. Cara shall be taken to minimiza changas ingeometry that may cause stress concentrations. The trame shall be designed for rated loado The ratedload stress shall not exceed 20 percent of the average ultimara strength of the material used. Wherestress concentrations exist, the stress as amplified by the appropriate amplification factor with dueconsideration for impact and service shall not exceed the endurance strength of the material used. Othermaterials agreed upon by the manufacturar and recognized as suitable for the appfication may be used,provided the parts are proportionate to give appropriate design 1actors.

4.2.2 The hook shall be of rolled steel, forged steel or a material agreed upon by the manufacturer andrecognized as suitable for the application. The hook shall be desígned based on the rated loado

4.2.2.1 The hook rated load stress shall be calculated considering the rated toad on the hook using:

A. Straight beam theory with the calculated combined stresses not to exceed 20 percent of the material'saverage ultimate strength.

-QR-

B. Modi1ied curved beam theory with the calculated combined stresses not to exceed 33 percent 01 thematerial's average ultimate strength. ~'., ;,;.

-QR- ;.;...¡

C. Plastic theory or testing with the combined stress es not to exceed 20 percent of the stress producedby the straightening load as obtained by test or calculation by this theory.

4.2.2.2 The hook shall rotate 1reely and be supported on a thrust bearing. The hook shank stress shall becalculated considering the rated load and shall not exceed 20 percent of the materíal's average ultimatestrength. At points of geometric discontinuities, the calculated stress as amplified by the appropriatestress ampli1ication factor with due consideration for impact and service shall not exceed the endurance

strength.

4.2.2.3 Other litting attaching devices, such as eye bolts and twist locks, shalt be designed to applicabte portionof Sections 4.2.2.1 and 4.2.2.2.

4.2.2.4 Load block sheave pins and trunnions shall be designed per the applicable Section 4.11.4 of this

specification.

4.3 OVERLOAD LlMIT DEVICE(-

4.3.1 An overload limiting device is normally only provided when speci1ied. Such device is an emergenl;Ydevice intended to permit the hoist to litt a freely suspended load within its rated capacity, but preventsfitting of an overload that would cause permanent damage to a properly maintained hoist, trolley or crane.

4.3.1.1 Variables experienced within the hoist system, such as, but not limited to, acceleration of the loads.dynamics of the system, type and length of wire rape, and operator experience, render it impossible toadjust an overload device that would prevent the litting of any overload or load in excess of rated loado

4.3.1.2 The adjustment 01 an overload device, when 1umished, will allow the fitting of an overload of suchmagnitude that will not cause permanent damage to the hoist, trolley, or crane, and shall prevent thefitting 01 an overload of such magnitude that could cause permanent damage to a properly maintainedhoist, trolley, or crane.

34

Page 36: CMAA 70

4.3.1.3 The over1oad device 18 actuated only by loads incurred when lifting a freely suspended load on the hook.Therefore, an overload device cannot be relied upon to render the hoisting mechanism inoperative ifother sources, such as but not limited to, snagging of the load, two blocking of the load block. orsnatching

a loado induce loads into the hoisting system.

4.3.1.4 The overload limit device is connected into the hoisting control circuit and, therefore. will not preventdamage to the hoist, trolley, or crane, if excessive overloads are induced into the hoisting system when

the hoisting mechanism is in a nonoperating or static mode.

4.4 HOISTING ROPES

4.4.1 The hoisting rope shall be of proper design and construction for crane service. The rated capacity loadplus the load block weight divided by the number of parts of rope shall not exceed 20 percent of thepublished breaking strength of the rope except rapes used for holding or lifting molten metal which shall

not exceed 12.5 percent of the published breaking strength of the rape.

4.4.2 The wire rape construction shall be as specified by the crane manufacturero When extra strength steelor wire center rope is used, the crane manufacturer's specifications shall so state.

Wherever exposed to temperatures at which fibre cores would be damaged, ropes having anindependent wire-rope. wire strand core, or other temperature-resistant core shall be used.

4.4.3 Rope Fleet Angle

4.4.3.1 Rope fleet angle for drums. The fleet angle of the rape should be limited to 1 in 14 slope (4 degrees) as

shown in Figure 4.4.3.1-1.

4.4.3.2 Rope fleet angle for sheaves. The fleet angle of the rape should be limited to 1 in 12 slope (4 degrees-

45 minutes) as shown in Figure 4.4.3.2-1.

e Groove

------.~ prum -

--- ---

40 Fig. 4.4.3.1-1 40 40 or 1 in 14 Slope

<t

4045'or

1 in 12 900

Slope L.,1 ---"'" ---

Fig. 4.4.3.2-1 Sheave

35

-.-1111111-' , ;,:o_.

Page 37: CMAA 70

4.4.4 The CMAA recornmended sheave and drum to rope diameter ratlos have been found by experience tIgive satisfactory performance over a wide range of applicatlons. Wlre rope is considered a consumabllmaintenance item. The wire rape maintenance interval will tend to be lengthened by:

-increasing sheave and drum to rape diameter ratio-minimizing the number of rape bends-minimizing reverse rape bends-minimizing drum to sheave and sheave to sheave fleet angles

4.5 SHEA VES

4.5.1 The sheave shall be steel or mínimum ASTM grade A48-latest edition, Glass 40 cast iron or othersuitable materials as specified by the crane manufacturero

4.5.2 Table 4.5.2-1 is a guide for pitch diameter of running sheaves. Smaller sheaves may cause an increasein rope maíntenance.

TABLE 4.5.2-1GUIDE FOR MINIMUM PITCH DIAMETER OF RUNNING SHEAVES

CMAACIasa 8 x 37 Class Rape 8 x 19 Clasa Aope

A & B 18 } 20 }C 18 24 " .

D 20 x d 24 x d C~E 24 30F 30 30

d .rope diameter

4.5.3 The pitch diameter of equalizer sheaves should not be less than one-half of the diameter of runningsheaves, and also shall not be less than 12 times the rope diameter when using 6 x 37 class rape or 15times the rope diameter for 6 x 19 class rope.

4.5.4 When special clearance, lift or low headroom is required, it may be necessary to deviate from these

limitations.

4.6 DRUM

4.6.1 The drum shall be designed to withstand sil combined loads, including crushing or buckling, bending,torsion and shear, with consideration for stress reversals and fatigue, consistent with the service and

manufacturing process.

The drum material shall be as specified by the crane manufacturer. Gast iron drums shall be AST~ 'deA48-latest edition, Glass 40 or equal. Gast steel drums shall be ASTM A27 or equal. Welded steell. ~ms

shall be ASTM A36 or equal.

If a welded drum is used, refer to Table 2.8-1 to determine the service class based on the actual cyclesof the drum. Stresses shall be evaluated usíng criteria defined in Section 3.4.7.

4.6.1.1 The drum shaft shall be designed per the applicable Section 4.11.4 of thís specification.

4.6.2 The drum shall be so designed that not less than two wraps of hoisting rope will remain on eachanchorage when the hook is in íts extreme low position, unless a lower limit device is provided, in whích

--case no les s than one wrap shall remain. No overlap of the rope shall be permitted when the hook is at

its high point.

4.6.3 Drum grooves shall be machined. Grooving should be right and left hand unless otherwise specified by

the crane manufacturero

36

-.

~

Page 38: CMAA 70

4.6.3.1 Recommended minimum drum groove depth is .375 x rope diameter.

4.6.3.2 Recommended mínimum drum groove pítch is either 1.14 x rope diameter or rope diameter + 1/8 inch,whichever is smaller.

TABLE 4.8.4-1

GUIDE FOR MINIMUM PITCH DIAMETER OF DRUMS

~~ 6 x 37 C/ass Rape 6 x 19 C/ass Rape

A & B 16 } 20 }C 18 24

D 20 xd 24 xdE 24 :M>F 30 :M>

d -rope diameter

4.6.4 Table 4.6.4-1 is a guide for minimumpitch diameter of drums. Smaller drums may cause an increasein rope maintenance.

4.6.5 When special clearance, lift or low headroom is required, it may be necessary to de vi ate from these[ limitatíons.\;.

4.7 GEAR/NG

4.7.1 The types of gearing shall be specified by the crane manufacturer. When worm gearing ís used for traveldrives, considerarían should be given to its backdriving characteristícs.

4.7.2 AII gears and pínions shall be constructed of material of adequate strength and durabílíty to meet therequirements for the intended class of service. and manufactured to American Gear ManufacturersAssociation (AGMA) quality class 5 or better.

For the purpose of thís specification, hoist gearing strength and durabílity shall be based on thehorsepower required to lift the rated loado Travel gearing strength and durability shall be based on themotor name plate rating. Due consideration shall be given to the maximum brake torque which can beapplied to the drive. Also, consideration shall be given to the fact that gearing for travel drives transmita larger portíon of the available motor torque than gearing for hoist drives.

4.7.3 The horsepower rating for all spur and helical gearing shall be based upon AGMA Standard 2001-C95(Fundamental Ratíng Factors and Calculation Methods for Involute Spur and Helical Gear Teeth). Forthe purpose of this specification, the horsepower formulae may be written:

Allowable strength horsepower-

[ Npd ] ~ F Sal J ~P a. = 1""2600Q""K: L Km P cI Sta K:)

Allowable durabilíty horsepower-

[ N F I ] [S d Gil] 2

P 8C = L12600i""K:""i<: ~ ~ ~

37

Page 39: CMAA 70

., where: P. -allowable strength horespower -!~I;;::i;:~~,';

P K -allowable durability horsepower "'; i .

NO -pinion speed (rpm)d -pitch diameter of pinion (inches)~ -dynamic factor (strength and durability)F -net face width of the narrowest of the mating gears (inches)~ -load distribution factor (strength and durability)

C -elastic coefficientp

CII -hardness factor (durability)J -geometry factor (strength)I -geometry factor (durability)

P d -diametral pitchKg -rim thickness factorS. -allowable bending stress for material (psi) (strength)Sc -allowable contact stress for material (psi) (durability)

S- -crane class factor (strength)S~ -crane class factor (durability)

Valuesforll ,K ,C ,Ch,J,l,1( ,S t andS can bedeterminedfromtablesand curves in AGMA Standard

"v m O "8 8 8C2001-C95. Crane class factor S,. is tabulated in Table 4.7.3-1 and S~ shall be the product of themachinery service factor (Cd) and the load factor (K.), [SId = Cd X ~. For Cd, refer to Section 4.1.3 and

for K , refer to Section 4.1. The remaining values pertain to gear size and speed.w

TABLE 4.7.3-1 ~

CRANE CLASS FACTORS FOR STRENGTH HORSEPOWER RATlNG

Crane Class S,.

A .75

B .85

C .90

D .95

E 1.00

F 1.05

These factors are not to be used in sizing any commercial gearboxes. AII

commercial gearboxes are to be sized according to gearbox manufacturer's

recommendations.(

4.7.4 Means shall be provided to insure adequate and proper lubrication on all gearing.

4.7.5 AII gearing not enclosed in gear cases which may constitute a hazard under normal operating conditions

shall be guarded with provision for lubrication and inspection.

4.7.5.1 Guards shall be securely fastened.

4.7.5.2 Each guard shall be capable of supporting the weight of a 200 pound person without permanentdistortion, unless the guard is located where it is impossible to step on. -

38

-.-

a

Page 40: CMAA 70

4.8 BEARINGS 1111118 I4.8.1 The type of bearíng shall be as specified by the crane manufacturero

4.8.2 Anti-friction bearings shall be selected to give a minimum rife expectancy based on full rated speed asfollows:

TABLE 4.8.2-1AFBMA L,c BEARING LlFE

Class A 1250 Hours

Class B 2500 Hours

Class C 5000 Hours

Class O 1 0000 Hours

Class E 20000 Hours

Class F 40000 Hours

Use the appropriate ~ load factor for all applications as determined in Section 4.1 and 4. 13.3 of this

specification.

Due consideration shall be given to the selection of the bearing in the event a crane is used for a limitedtime at an increased service class such as:

Example-'during a construction phase.'

4.8.3 Sleeve bearings shall have a maximum allowable unit bearing pressure as recommended bythe bearingmanufacturer.

4.8.4 AII bearings shall be provided with proper lubrication or means of lubrication. Bearing enclosures shouldbe designed as lar as practicable to exclude dirt and prevent leakage of oil or grease.

4.9 BRAKES

4.9.1 Hoist Holding Brakes

4.9.1.1 Each independent hoisting unir of a crane shall be equipped with at least one holding brake. This brakeshall be applied directly to the motor shaft or some other shaft in the hoist gear train.

4.9.1 .2 Hoist holding brakes shall have minimum torque ratings, stated as a percentage of the rated load hoistingtorque, at the point where the holding brake is applied as follows:

4.9.1.2.1 125 percent when used with a control braking means other than mechanical.

-4.9.1.2.2 100 percent when used with mechanical control braking means.

4.9.1.2.3 100 percent for each holding brake if two holding brakes are provided.

4.9.1.3 Hoist holding brakes shall have thermal capacity for the frequency of operation required by the service.

4.9.1.4 Hoist holding brakes shall be provided with means to compensate for lining wear.

4.9.1.5 Each independent hoisting unit of a crane that handles molten materials shall have one of the following

arrangements:

4.9.1.5.1 Two holding brakes (one of which is mounted on a gear reducer shaft) plus control braking means shallbe provided. Each brake shall have a minimum torque rating equal to rated load hoisting torque at thepoint where the brake is applied.

4.9.1.5.2 If the hoist unir has a mechanicalload brake or a controlled braking means that provides emergencybraking in the lowering direction upon loss of power, only one holding brake is required. The holdingbrake shall have a minimum torque rating equal to 150 percent of the rated load hoisting torque at thepoint where the brake is applied.

39

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Page 41: CMAA 70

F

4.9.2 HoIst Control Br8kJng M_M' ..4.9.2.1 Each independent hoisting unit of a crane, except worm-geared hoists, the angie of whose worm is such

." as to prevent the load fr?m accelerating in the lowering direction, shall be equipped with control braking

¡,i;B means to controllowerlng speeds.

4.9.2.2 Control braking means shall be mechanical, hydraulic, pneumatic or electric power (such as eddycurrent, dynamic, regenerative or counter torque). AII methods must be capable of maintainingcontrolled lowering speeds. The inherent regenerative controlled braking means of a squirrel cage motormay be used if the holding brake is designed to meet the additional requirement of retarding a decendingload upon power removal.

4.9.2.3 Hoist control braking means shall have thermal capacity for the frequency ot operation required by

the service.

4.9.3 Trolley Brakes

4.9.3.1 On cab operated (non-skeleton) cranes with cab on trolley, a trolley brake shall be provided havingtorque capability to stop the trolley motion within distance in feet aquel to 10 percent of retad load speedin feet per minute when traveling at rated speed with rated loado

4.9.3.2 On cab-operated (non-skeleton) cranes with cab on bridge, a trolley brake or non-coasting mechanicaldrive may be provided when specified. When provided, the brake or non-coasting mechanical dri'(~ ~IImeet the stop travel distance requirements ot Section 4.9.3.1 -

4.9.3.3 On floor, remota or pulpit-operated cranes, including skeleton cab-operated cranes, a trolley brake ornon-coasting mechanical drive may be provided when specified. When provided, the brake or non-coasting mechanical drive shall meet the stop travel distance requirements of Section 4.9.3.1.

4.9.3.4 Trolley brakes, when provided, shall ha ve thennal capacity tor the freque~y ot operation required by

the service.

4.9.3.5 It a trolley parking brake is provided. it should have a torque rating of at least 50 percent of the rated motor

torque.

4.9.3.6 A drag brake may be applied to hold the trolley in a desired position on the bridge and to eliminate creep

with the power off.

4.9.3.7 The minimum requirements for trolley brakes and braking means per ANSVASME B30.2 is shown in

Figure 4.9.3.7-1.

,FIGURE 4.9.3.7-1 "

Trolley Brakes

CAB OPERA TED FLOORAttached to Attached to Remote or Pulpit

Trolley Bridge OperatedIndoor Outdoor Indoor Outdoor Indoor Outdoor

Service Service Drag Drag Emergency or Emergency orEmergency Emergency Drag or Non- Drag or Non-

--Parking Coasting CoastingMechanical MecnanicalDrive Drive

~ A TROLLEY BRAKE IS REQUIRED.

~ A TROLLEY BRAKE IS NOT REQUIRED.40

.

~

Page 42: CMAA 70

4.9.4 Bridge Brakes -

4.9.4.1 On cab-operated (non-skeleton) cranes. a bridge brake shall be required having torque capability to stopthe bridge motion within a distance in feet equal to 10 percent of rated load speed in feet per minute whentraveling at rated speed with rated loado

4.9.4.2 On floor. remate or pulpit-operated cranes including skeleton (dummy) cab-operated cranes. a bridgebrake or non-coasting mechanical drive shall be required having torque capability to stop the bridgemotion within a distance in feet equal to 10 percent of rated load speed in feet per minute when travelingat rated speed with rated loado

4.9.4.3 Bridge brakes, when provided, shall have thermal capacity for the frequency of operation required by

the service.

4.9.4.4 If a bridge parking brake is provided. it should have a torque rating of at least 50 percent ofthe rated motor

torque.

4.9.4.5 On cranes designed with high speed and high acceleration rates, consideration should be given toprovide braking means to achieve proportionally high deceleration rates.

4.9.5 General Brake Comments for Normal Cab-Operated Cranes.

4.9.5.1 Foot operated brakes shall require an applied force of not more than 70 pounds to develop rated brake

torque.

4.9.5.2 Brake pedals, latches, and levers should be designed to allow release without the exertion of greaterforce than was used in applying the brake.

4.9.5.3 Brakes should be applied by mechanical, electrical, pneumatic. hydraulic or gravity means.

4.9.5.4 AII foot-brake pedals shall be constructed so that the operator's foot will not readily slip off the pedal.

4.9.5.5 Foot-operated brakes shall be equipped with a means for positive release when force is released from

the pedal.

4.9.5.6 The foot-brake pedals should be so located that they are convenient to the operator at the controls.

4.9.5.7 If parking brakes are provided on the bridge or trolley, they shall not prohibit the use of a drift point in

the control circuito

4.9.5.8 The minimum requirements for bridge brakes and braking means per ANSI B30.2.0 is shown in Figure

4.9.5.8-1.

FIGURE 4.9.5.8-1Bridge Brakes

CAe OPERA TED FLOOR

Attached to Attached to Remote or Pulpit

Trolley Bridge OperatedIndoor Outdoor Indoor Outdoor Indoor Outdoor --0.;;..0.

Service Service Service Service Emergency or Emergency or '-.

Emergency Emergency Drag or Non- Drag or Non-

Coasting CoastingMechanical MechanicalDrive Drive

41

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Page 43: CMAA 70

4.10 BRIDGE DRIVES -

4.10.1 Bridge drives shall consist ot one ot the tollowing arrangements. as specified on information sheets andas illustrated in Figure 4.10.1-1, These arrangements cover most tour or eight wheel crane drives. Forthe number of driven wheels tor a specific acceleration rate-refer to the electrical Section 5.2.9.1.2.1

A & 8 of this specification,

FIGURE 4.10.1.1ARRANGEMENT OF CRANE BRIDGE DRIVES

A1 DRIVE

A2 DRIVE

r~,

,r- q, CRANE

A3 DRIVE

_..1_- I - t .-., r "... n ., '. , , .' .?-o-' --" -.M DRIVEI.'L l 1-' l ".. t '., ,... -,- ~.' ~.I '..~ -'1

q, CRAN E

(AS DRIVE

I

r- q, CRAN E

-.-

AS DRIVE

42~ .-

L ~~ -~.' ..

Page 44: CMAA 70

,.

4.10.1.1 A-1 Drive: The rootor is Iocated near the center of the bridge and IXII-.-II*: m a self-contained gear ",

reduction unit kx:ated near the center of the bridge. Output of the gear ~~ shall be connected.directly to the truck wheel axles by means of suitable shafts and coupi'1gs.

4.10.1.2 A-2 Drive: The motor is connected to a self-contained gear reduction unit kxated near the center of thebridge. The truck wheels shall be driven through gears pressed and keyed on their axles or by gearsfastened to, or integral with, the truck wheels and with pinions mounted on the end sections of the cross-shaft. The end sections of the cross-shaft shall be connected by suitable couplings.

4.10.1.3 A-3 Drive: The motor is located at the center of the bridge and is connected to the cross-shaft and thegear reduction units with suitable couplings. Self-contained gear reduction units located near each endof the bridge shall be either directly connected to the wheel axle extension or connected to wheel axlesby means of shafts with suitable couplings.

4.10.1.4 A-4 Drive: The motors are located near each end of the bridge without torque shafts. The motors shailbe connected to self-contained gear reduction units. The gear reduction units shaJl be applied to the truckwheels by means of either suitable shafts and couplings or directly mounted to the wheel axle shaftextension. Another variation of this drive would separate the high speed aro final reductions by locatingthe motors near each end of the bridge without torque shafts. The motors will be connected to self-contained high Speed gear boxes which will drive the truck wheels through gears pressed and keyedon their axles or by gears fastened to the truck wheels, and with pin ions mounted on the end sectionon the shaft from the high speed gear box and the final reduction shall be connected by means of suitableshafts and couplings.

( 4.10.1.5 A-5 Drive: The motor is located near the center of the bridge and is connected to a self-contained gear

reduction unit located near the center of the bridge. This reduction unit shall be connected by sectionsof cross-shaft having suitable couplings to self-contained gear reduction units k>cated near each end ofthe crane, and these in tum connected to truck wheel axles by means of shafts with suitable couplings.

4.10.1.6 A-6 Drive: The motors are located near each end of the bridge and connected with a torque shaft. Onthe drive end, the motors shall be connected to self-contained gear reduction units by suitable couplings.The output of the gear reduction units shall be connected directly to the truck wheel axle by means 01suitable shafts and couplings.

4.11 SHAFTING

4.11.1 General Nomenclature and Values for Section 4.11

TABLE 4.11.1-1SURFACE CONDITION FACTOR

K SURFACE CONDITION8C

1 .4 For Polished-Heat treated and inspected shafting

1.0 For Machined-Heat treated and inspected shafting

.75 For Machined-General usage shafting

TABLE 4.11.1-2

CRANE CRANECLASSFACTOR ~CLASS Kc

A 1.0B 1.015C 1.03D 1.06E 1.125F 1.25

--43

.

Page 45: CMAA 70

0'. = endurance strength of shaft material = .36 O' K.-11 K

O' u = average tensile strength 01 shaft material

O' um = minimum tensile strength 01 shaft material

O'yp = minimum yield strength 01 shaft material

O' av = portion 01 the tensile stress not due to 11uctuating loads

tJ:v = partían of the shear stress not due to fluctuating loads

O' R = portion of the tensile stress due to fluctuating loads

'1;: = portion of the shear stress due to fluctuating loads

~ = stress amplification factor 10r bending

~ = stress amplification factor 10r direct tension

KST = stress amplification factor 10r torsional shear

Kgv = stress amplification factor for transverse shear

K = crane class factorc

K = surface condition factorK

4.11.2 AII shafts, except the bridge cross-shaft sections which do not carry gears, should be cold rolled shaftingquality or better. The shaft diameter and method of support shall be as specified by the crane

manufacturero

The bearing spacing for rotating shafts less than 400 rpm shall not exceed that calculated per:l '

.."-

L = ij 432,000 D2

L = Distance between bearing centers (inches)D = Shaft diameter (inches)

When the shaft speed exceeds 400 rpm, the bearing spacing shall not exceed that determined by the101l0wing formula, or the preceeding formula whichever is less in arder to avoid objectionable vibration

at critica! shaft speeds:

L = \!;~~~~~E~1.2 N

L = Distance between bearing centers (inches)D = Shaft diameter (inches)N = Maximum shaft speed (rpm)

4.11.3 The torsional de11ection of the bridge cross-shaft shall not exceed the values shown on Table 4."". ~-

1. The types 01 drive referred to on the table are as defined in Section 4.9 and the percent motor to ~is the portion 01 the 1ullload torque 01 the bridge drive motor(s) at its normal time rating 10r the serviceinvolved, increased by any gear reduction between the motor and the shaft. The allowable angulardeflection is expressed in degrees perfoot. In addition the total angular deflection produced by the motortorque in Table 4.11.3-1 should result in a bridge drive wheel movement no greater than 1 percent ofthe wheel circumference or 0.5 inch on the circum1erence, whichever is less.

TABLE 4.11.3-1MAXIMUM ANGULAR DEFLECTION DEGREES PER FOOT

Type 01 Percent Cab Controlled Floor & Remote -

Drive Motor Torque Cranes Controlled Cranes

A1 67 .080 0.10A2 50 .080 0.10A3 67 .080 0.10A4 100 .070 0.10A5 50 .080 0.10A6 100 .070 0.10

44

Page 46: CMAA 70

4.11.4 Stres. Calculatlons

AII shafting shall be designad to meet the stresses encountered in actual operation. For the purposesof this specification, the strength shall be based on the torque required to lift the rated 'Dad for hoistmachinery and the motor nameplate rating for drive machinery. Due consideration shall be given to themaximum brake torque which may be applied to the shaft. When significant stresses are produced byother forces, these forces shall be positioned to provide the maximum stresses at the section underconsideration. Impact shall not be included.

4.11.4.1 Static Stress Check for Normal Operating Conditlons

A. For shafting subjected to axiaJ loads, the direct tensile stress shall be calculated as follows-(except when buckling needs to be considerad)

0'0 = P/A ~ O'ul Swhere:P = axialloadA = cross sectional Brea

B. For shafting subjected to bending moments, the tensile stress shall be calculated as follows-

O's = Mr/1 ~ O'u/Swhere:

r M = bending moment at section~.,. r = outside radius of shaft

I = bending moment of inertia

C. For shafting subjected to torsionalloads, the torsional shear stress shall be calculated as follows-

~ = Tr/J ~ O'u/ (SV3 ).where:T = torquer = outside radius of shaftJ = polar moment of inertia

D. For shafting subjected to transverse shear loads, the stress shall be calculated as follows-

For salid shaft, ~ = 1.33 V/A ~ O'u/ (S V3 ).

For hollow shaft, ~ = 2 V/A ~ O'u/ (S V3).

,..-"' where:V = shear load at sectionA = cross sectional Brea

E. When combinations 01 stresses are present on the same sectional element, they should becombined as follows-

Direct axial and bending stress es

O'I = 0'0 + O's ~ O'u/S

~ T orsional and transverse shear stresses

~ = '1; + ~ ~ O'u/ (S'V'3 ).

Combined direct axial and bending with torsional shear:

O'COMB = V<O'J2 + 3('1;}2 ~ O'u/S'- 4S

Page 47: CMAA 70

f Note: For simply loaded shafting, bending and torsional stresses are maximum on the outer fibf;..: of the shaft and must be combtned. The transverse shear stresses are maxlmum 00 h neut

-axis of the shaft and combine with the torsional stresses but not with the bending stresses.

4.11.4.2 Fatigue Stress Check for Normal Operating Cond/tlons

Any shafting subjected to fluctuating stresses such as the bending on rotating shafts or the torsionreversing drives must be checked for fatigue. This check is an addition to those in section 4.11.4.1 alneed only be performed at points of geometric discontinuity where stress concentrations exist, such 'fillet radii, holes, keys, press fits, etc. This is accomplished by applying an appropriate streamplification factor to the respective nominal stresses (not combined) as determined in Section 4.1.4,The following outlines the design criteria:

~~ a. Direct axial and bending, CJF}: = ~CJD + ~CJ8 ~ +

i;

(J'b. Torsional and transverse shear, ~ = KST ~ + Ksv'Iv" S .

..Kc~,;¡

", c. For combined stresses when all of the direct axiaJ and bending stresses are combined with the: torsional stresses and all are fluctuating-

CJFCOMB ='1/ (CJF}:)2 + 3 (KST '1;)2 ~ + .

d. For combined tensile and shear stresses when only part of these stresses are fluctuating-

\ / r -.0'- ,2 -r..-YO" .cr. ..,-r- ,2[ O' 2 T O' tT ]2 0'.CJFCOMB = V LCJ.v (F-) + ~CJR] + 3[ .1.v (~) + Ks'~ J S ~

yp vyp "c

¡

4.11.5 Shafting in bearing must be checked for operating conditions. The bearing stress is ca~lated b~dividing the radialload by the projected area, ie, P/(d xL) where d is the shaft diameter and L is the lengtt-in bearing. This bearing stress must not exceed 50 percent of the minimum yield for non-rotatin~

shafting.

This bearing stress must not exceed 20 percent of the minimum yield for oscillating shafting when notlimited by the bushing material.

4.12 COUPL/NGS r.

4.12.1 Cross-shaft couplings, other than flexible type, shall be steel or minimum ASTM Grade A48, latestedition, Class 40 cast iron or equal material as specified by the crane manufacturer. The type of coupling(other than flexible) may be compression, sleeve or flange type. Flexible couplings shall be the cranemanufacturer's standard type.

4.12.2 Motor couplings shall be as specified by the crane manufacturero

4.13 WHEELS

4.13.1 Unless other means of restricting lateral movement are provided, wheels shall be double flanged withtreads accurately machined. Bridge wheels may have either straight treads ortapered treads assembledwith the large diameter toward the center of the span. Trolley wheels should have straight treads. Drivewheels shall be matched pairs within 0.001 inches per inch of diameter or a total of 0.010 inches on thediameter, whichever is smaller. When flangeless wheel and side roller assemblies are provided, theyshall be of a type and design recommended by the crane manufacturer.

46

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Page 48: CMAA 70

4.13.2 Wheels shall be rolled or forged from ~n hearth, basic oxygen or efectric fumace steel, or casI of anacceptable carbon or alloy steel wVess otherwise specified. WheeIs shall be heat treated onIy If

.specified. Other suitable materials may be used. Due consideration shall be given to the brittleness andimpact strength of the material used.

4.13.3 Slzlng of Wheels and Rails

Wheels shall be designed to carry the maximum wheel load under normal conditions without unduewear. The maximum wheelload is that wheelload produced with trolley handling the rated load in theposition to produce the maximum reaction at the wheel, not including VIF. When sizing wheels and rails,the following parameters shall be considered.

wheel diameter = D (inches)effective rail head width = W (inches)hardness coefficient of the wheel = Kwhere: K = BHN x 5 (for wheels with BHN ~ 260)

K = 1300 (BHN/260).33 (for wheels with BHN > 260)

The basic bridge and trolley recommended durability wheelloading for different wheel hardnesses andsizes in combination with different rail sizes are shown in Table 4.13.3-4. The values in the table areestablished by the product of D x W x K. In addition, the load factor, ~ or~, the speed factor Ca, and

;r the crane service class shall be considered.\,..

4.13.3.1 The load factor ~ for the trolley wheels is established by the following formula:

~ = (2Y rated loadfr) + 1.5 TW(3Y rated loadfr) + 1.5 TW

Where TW = trolley weight yT

The load factor ~ for the bridge wheels is established by the following formula or Table 4.13.3-1 maybe used for standard hook cranes in lieu of calculating the exact value for a particular application. Othercranes may require special considerations. The factors shown at 100-ton capacity may be used forcapacities above 1aO-tons.

~¡ .

X

SPAN

~ = .7S(BW) + f(LL) + .S(TW) -.Sf(TW).7S(BW) + 1.Sf(LL)

where: BW = bridge weight ~LL = trolley weight + rated load ¡,",

f = X/span

47

Page 49: CMAA 70

TA8LE 4.1Uo1 --" 111-

TYPICAL BRIDGE LOAD FACTORl K.. .

BRIDGE CAPAaTY IN TONSSPAN FT. 35m 10 15 20 21

20 .812 .782 .762 .747 .732 .722 .716

30 .817 .785 .767 .750 .736 .725 .718

40 .827 .794 .m .760 .744 .732 .723

50 .842 .809 .791 .771 .758 .740 .738

60 .861 .830 .807 .790 .773 .754 .747

70 .877 .844 .825 .807 .789 .768 .760

80 .888 .857 .835 .818 .802 .779 .770

90 .898 .869 .850 .832 .815 .792 .782

100 .912 .883 .867 .848 .826 .a .796

110 .926 .890 .882 .863 .844 .823 .812

120 .934 .909 .894 .879 .860 .834 .827

TABLE 4.13.3-1 .Contlnued

TYPICAL BRIDGE LOAD FACTORS K.. f1::'

BRIDGE CAPACfTY IN TONSSPAN FT 30 35 40 50 80 75 100

20 .716 .714 .713 .713 .709 .709 .708

30 .718 .715 .713 .711 .708 .~ .706

40 .723 .722 .717 .714 .711 .711 .708

50 .731 .728 .723 .720 .718 .715 .711

60 .741 .736 .729 .728 .722 .721 .717

70 .752 .746 .738 .734 .729 .727 .723

80 .761 .754 .746 .742 .738 .735 .730

90 .774 .767 .758 .754 .747 .744 .737

100 .786 .780 .770 .783 .758 .753 .745

110 .800 .793 .782 .777 .768 .762 .755

120 .814 .807 .797 .790 .782 .774 .763

r

:~:,

48

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~

Page 50: CMAA 70

,

4.13.3.2 The speed factor C. depends on the rotational speed of the wheeI and ti Usted In T abIe 4.13.3-2. These

factors are obtained from the following formulas:

.",'

for RPM s 31.5 C. = [1 + (B~~io~~)]2 ~~:

for RPM > 31.5 C. = 1 + (B~~2~~~~)

TABLE 4.13.3-2

SPEED FACTOR C.WHEEL SPEED IN FEET PER MINUTE

OlA.ININCHES 30 50 75 100 125 150 175 200 250 300 350 400

8 .907 .958 1.013 1.049 1.086 1.122 1.158 1.195 1.267 1.340 1.413 1.4859 .898 .944 1.001 1.033 1.066 1.098 1.130 1.163 1.227 1.292 1.356 1.421

10 .892 .932 .984 1.0201.0491.0791.108 1.137 1.195 1.253 1.3111.36912 .882 .915 .958 1.0011.0251.0491.0741.0981.1461.1951.243 1.292

15 .872 .898 .932 .967 1.0011.0201.040 1.059 1.098 1.1371.1751.21418 .865 .887 .915 .944 .973 1.0011.0171.033 1.066 1.0981.130 1.16321 .860 .879 .903 .927 .952 .977 1.001 1.015 1.043 1.070 1.098 1.12624 .857 .873 .894 .915 .937 .958 .980 1.001 1.025 1.049 1.074 1.09827 .854 .869 .887 .906 .925 .944 .963 .982 1.012 1.033 1.055 1.07630 .852 .865 .882 .898 .915 .932 .949 .967 1.001 1.020 1.040 1.05936 .849 .860 .873 .887 .901 .915 .929 .944 .973 1.001 1.017 1.033

4.13.3.3 The wheel service factor Sm is equal to 1.25 times the machinery service factor Cd and is shown in theTable 4.13.3-3 for the different service classifications. This factor recognizes that the interactionbetween rail and wheel is more demanding in terms of durability than well aligned and lubricated

interaction of machined parts.

4.13.3.4 The trolley load service coefficient K.. = ~ x C. X Sm and the bridge wheelload service coefflcient

r K.. = ~ x C. X Sm with the following limitations:\

K.. may not be smaller than Kwl mino shown in Table 4.13.3-3.

4.13.3.5 The equivalent durability wheelload P. shall be determined as follows:

P .= Max. wheel load x KwI

The equivalent durability wheelload P. shall not exceed wheelloads listed in Table 4.13.3-4.

4.13.§- Proper Clearance for Bridge Wheels

A total of approximately 3/4 inch to one inch wider than rail head should be provided between the wheelflanges and rail head. Tapered tread wheels may have a clearance ayer the rail head of 150 percent ofthe clearance provided for straight tread wheels as recommended by the crane manufacturer.

When rotating axles are used. wheels should be mounted on the axle with a press fit alone. press frt and

keys. or with keys alone.49

Page 51: CMAA 70

-TABLE 4.13.3-3

WHEEL SERVICE FACTOR Sm AND MINIMUM LOAD SERVICE FACTOR K.. MINIMUM

CLASS OF ACRANESERVlCE B C D E F

K.., MIN .75 .75 .8 .85 .9 .95

S.. .8 .9 1. 1.12 1.25 1.45

TABLE 4.13.3-4

MAXIMUM PERMISSIBLE BRIDGE AND TROLLEY WHEEL LOADING (POUNDS)

ASCE

i Wheel ASCE 80 & 85#

: Wheel dia. ASCE ASCE ASCE ASCE ARA-A 60 & 70. ARA-A ASCE BETH BETH BETH

~ (D) rol 25# 30# 40. 90. ARA-B 100. 1001 & USS &USS 1711

inches 1001 BETH 104 1351 1751

1

8 6750 8000 8500 10000

9000 9550 11250 14900 15750

~~ ..}- ,,:

12000 12750 15000 19850 21000 22500 25500

200 15 15950 18750 24850 26250 28150 31850

..~ cf! .-.BHN .-, l'

21 26250 34800 36750 39400 44600 47250 65600 7350<

24 .-, 39750, 42000 -45000 .51CXX> 54000 75000 8400, I

.., ,," -} -".- J ". ¡ !

30 56250 63750 67500 93 I36 76500 81000 112 I

8 8800 10400 11050 13000

12450 14600 20450

..

27300 29250 33150

34100 36550 41450

260 ",' ;:,¡, .' ~ .:

BHN 58(XX) 61400 85300 9555<

66300 70200 97500 10920<

-(

82850 87750 121850 13650

99450 105300 146250 16380'

320BHN ,.

.

27200

58Rc

(615

BHN)

30 97150 110100 116600 161900 181350

36 132100 139900 194300 217600

Effective Width o,

Rail Head (W)Inches .844 1.000 1.063 1.250 1.656 1.750 1.875 2.125 2.250 3.125 3.500

(Top o, head minus

comer radii)

Notes 1 .Allowable wheet ioads lor hardened wheels requlre depth 01 hardness sufficient 10 withstand subsurface shear slresses.

2. The 58Rc loads are based on wheels r\X1rung on heat-Irealed rail (320 BHN mlnimum) 1I Ihe wheels ara runtw-.g on untreated rail, the above loads

may cause decreased raillile.

3. The RclBHN converslon is based on ASTM E140, tungsten carbide ball

4 Some raíl slzes may be out 01 pro<XJctio1.

50

,;""lff ~ I'~"!

Page 52: CMAA 70

4.14 BUMPERS

4.14.1 Bridge bumpers -A crane sha" be provided with bumpers or other means provlding equivalent effect,unless the crane has a high deceleration rafe due to the use of sleeve bearings, or is not operated nearthe ends of bridge travel, or is restricted to a limited distance by the nature of the crane operation andthere is no hazard of striking any object in this limited Brea. These bumpers, when used, sha" have thefollowing minimum characteristics:

4.14.1.1 Have energy absorbing (ordissipating) capacity to stop the crane when traveling with poweroff in eitherdirection at a speed of at least 40 percent of rated load speed.

4.14.1.2 Be capable of stopping the crane (not including load block and lifted load unless guided vertical'y) at arafe of deceleration not to exceed an average of 3 leer per second per second when traveling with poweroff in either direction at 20 percent of rated load speed.

4.14.1.3 Be so mounted that there is no direct shear on bolts upon impacto

4.14.2 Bumpers shall be designed and installed to minimize parts falling from the crane in case of breakageor loosening of bolted connections.

4.14.3 When more than one crane is located and operated on the same runway, bumpers shall be providedon their adjacent ends or on one end of one crane to meet the requirements of Sections 4.14.1.1 thru

C 4.14.2.

,,' 4.14.4 It is the responsibility of the owner or specifier to provide the crane manufacturer with information for

bumper designo Information necessary for proper bumper design includes:

4.14.4.1 Number of cranes on runway, bridge speed, approximate weight, etc.

4.14.4.2 Height of runway stops or bumper above the runway rail.

4.14.4.3 Clearance between cranes and end of runway.

4.14.5 Trolley Bumpers -A trolley shall be provided with bumpers or other means of equivalent effect, unlessthe trolley is not operated near the ends of trolley travel, or is restricted to a limited distance of the bridgegirder and there is no hazard of striking any object in this limited area. These bumpers. when used, shallhave the following minimum characteristics:

4.14.5.1 Have energy absorbing (or dissipating) capacity to stop the trolley when traveling with power off in eitherdirection at a speed of at least 50 percent of rated 'Dad speed.

.,-, 4.14.5.2 Be capable of stopping the trolley (not including load block and lifted load unless gu;ded vertical'y) atarate of deceleration not to exceed an average of 4.7 feet per second per second when traveling withpower off in either direction at 1/3 of rated load speed.

4.14.5.3 Be so mounted that there is no direct shear on bolts upon impacto

4.14.6 Bumpers shall be designed and installed to minimize parts falling from the trolley in case of breakage.

4.14.7 When more than one trolley is operated on the same bridge, bumpers shall be provided on their adjacentends or on one end of the trolley to meet the requirements of Sections 4.14.5.1 thru 4.14.6.

4.14.8 Trolley stops shall be provided at the limit of the trolley travel, and shall engage the tu" surface of the

bumper.

4.14.9 Trolley stops engaging the tread of the wheel are not recommended.

51

Page 53: CMAA 70

4.15 STOPS

4.15.1 Runway stops are normally designed and provided by the owner or specifier.

4.15.2 Stops are located at the limits of the trolley and bridge travel and shall engage the tull surface of thebumper.

4.15.3 Stops engaging the tread of the wheeJ are not recommended.

Cj

r

~

52

Page 54: CMAA 70

-70-5 ELECTRICAL EQUIPMENT

5.1 GENERAL

5.1.1 The electrical equipment section of this specification is intended to cover top running bridge and gantrytype, multiple girder electric overhead traveling cranes for operation with altemating current or directcurrent power supplies.

Cranes for alternating current power supplies may be equipped with squirrel cage and wound rotormotors with compatible control for single speed, multi -speed or variable speed operation. Cranes fordirect current power supplies, or altemating current power supply rectified on the crane, may beequipped with series, shunt or compound wound motors with compatible control for single speed orvariable speed operation.

5.1.2 The proposal of the crane manufacturer shall include the rating and description of al! motors, brakes,control and protective and safety features.

5.1.3 The crane manufacturer shall furnish and mount sIl electrical equipment, conduit and wiring, unlessotherwise specified. If it is necessary to partially disassemble the crane for shipment, all conduit andwiring affected shall be cut to length and identified to facilitate reassembly. Bridge conductors, runwaycollectors and other accessory equipment may be removed for shipment.

5.1.4 Wiring and equipment shall comply with Article 610 of the National Electrical Codeo~

(; 5.1.5 Electrical equipment shall comply with ANSI/ASME B30.2 Safety Standard for Overhead and Gantry

Cranes.

5.2 MOTORS-AC AND DC

5.2.1 Motors shall be designed specifically for crane and hoist duty and shall conform to NEMA StandardsMG 1 or AISE Standards No. 1 or 1 A, where applicable. Designs not in accordance with these standardsmay be specified.

5.2.1.1 AC induction motors may be wound rotor (slip ring) or squirrel cage (single speed or multi-speed) types.

5.2.1.2 DC motors may be series, shunt. or compound wound. or permanent magnet type.

5.2.1.3 AC Motors used wlth Inverters:

5.2.1.3.1 Motors shall be AC Induction (Iow slip) type.

r 5.2.1.3.2 Motor construction shall be TENV. TEFC, motor with independent blower, or open drip proof type.

5.2.1.3.3 Motor insulation should be Class F rated and should be thermally protected with sensor embedded inthe motor winding.

5.2.1.3.4 Motor selection shall be based on proper horsepower calculation for the drive of the required serviceclass. The motor's duty rating should be based on the service class and on the speed range requiredfor the application.

5.2.2 Motor Insulatlons

~ Unless otherwise specified by the crane manufacturer. the insulation rating shall be in accordance withTable 5.2.2-1.

53-.

Page 55: CMAA 70

~"TABLE 6.2.2-1 '

NEMA PERMISSIBLE MOTOR WINDING TEMPERATURE RISE,ABOVE 40 DEGREES C AMIBIENT, MEASURED BY RESISTANCE * +

A.C. MOTORS D.C. MOTORS

Insulation Open DripproofClass & TEFC TENV Open DrWroof TEFC & TENV

B 80 DEG. C 85 DEG. C 100 DEG. C 110 DEG. C

F 105 DEG. C 110 DEG. C 130 DEG. C 140 DEG. C

H 125 DEG. C 135 DEG. C 155 DEG. C 165 DEG. C

*If ambient temperatures exceed 40 Deg. C, the permissible winding temperature rise must be decreased by the same amount,

or may be decreased per the applicable NEMA Standards.

+ The crane manufacturer will assume 40 Deg. C ambient temperature unless otherwise specified by the purchaser.

5.2.3 Motors shall be provided with anti-friction bearings.

5.2.4 Voltage

Motor rated voltage and corresponding nominal system voltage shall be in accordance with Table 5.2.4-1 (References: AC-ANSI C84. 1-1977, Appendix and Table C3. DC-AISE Std. No. 1, RevisedSeptember 1968, Electrical2. Voltage Source and 3. Field Voltage; algo NEMA MG 1-10.62)

TABLE 5.2.4-1 .~NOMINAL SYSTEM AND MOTOR RATEDVOLTAGE

Nominal Motor

SOURCE DESCRIPTION System Rated

Voltage VoltageAC DC Three Phase Single Phase

120 -115

208 200-60 Hz (1) (2) 240 m 230

480 460-600 575-

50 Hz 400 380-

Adjustable VottageAC Shunt or Compound

Armature Shunt Fisld 400-3-60 230 4 230 5 ;

Rectlfled 240-3-60 240 150 or 240460-3-60 500 240 or 300

Constant Potentlal208 (9) Series, Shunt, Com undthru 360 M600 ex. 230 or 240 (3) (8)

Generator or -250 230 or 240 (3) (8)DC Battery

(1) Applicable to all nominal system voltages containing this voltage.

(2) For nominal system voltages other that shown above, the motor rated voltage should be either thesame as the nominal system voltage or related to the nominal system voltage by the approximateratio of 115 to 120. Certain kinds of equipment ha ve a maximum voltage limit of 600 volts; the

manufacturer and/or power supplier should be consulted to assure proper application.

54

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Page 56: CMAA 70

(3) Performance WllI not necessarily equal rated performance when appficable rippIe is presento

(4) Al SE Std. No. 1, Rev. 9-68 Electrical28 (mil motors).

(5) Al SE Std. No. 1, Rev. 9-68 Electrical 3 (mili motors).

(6) NEMA MG 1-10.62.2 & Table 10-9 (industrial motors).

(7) NEMA MG 1-10.62.2 & Table 10-10 (industrial motors).

(8) Rated Voltage may be 250 for large trames 300 HP, 850 RPM, and larger.

(9) Maximum motor input voltage.

5.2.4.1 Varlatlons -AC

5.2.4.1.1 Variatlon from Rated Voltage

AII AC induction motors with rated frequency and balanced voltage applied shall be capabJe ofaccelerating and running with rated hook load at plus or minus 10 percent of rated motor voltage, butnot necessarily at rated voltage performance values. (Reference NEMA MG 1-12.45)

, 5.2.4.1.2 Voltage Unbalance

(..'.. AC polyphase motors shall be capable of accelerating and running with rated hook load when the voltage

unbalance at the motor terminals does not exceed 1 percent. Performance will not necessarily be thesame as when the motor is operating with a balanced voltage at the motor terminals. (Reference NEMAMG 1-12.46)

5.2.4.2 Variatlons -DC

DC motors shall be capable of accelerating and running with rated hook load with applied armature andfield voltages up to and including 110 percent of the rated values of the selected adjustable voltage powersupply. With rectified power supp/ies successful operation shall result when AC line voltage variationis plus or minus 10 percent of rated voltage. Performance will not necessarily be in accordance with thestandards for operation at rated voltage. (Reference NEMA MG 1-12.68)

5.2.5 Operation with voltage variations beyond those shown in Sections 5.2.4.1 and 5.2.4.2. Operation atreduced voltage may result in unsatisfactory drive performance with rated hook load such as reducedspeed, slower acceleration. increased motor current, noise, and heating. Protective devices mayoperate stopping the drive in order to protect the equipment. Operation at eJevated voltages may result

r in unsatisfactory operation. such as, excessive torques. Prompt corrective action is recommended; the" urgency for such action depends upon many factors such as the location and nature of the load and

circuits involved and the magnitude and duration of the deviation of the voltage. (References ANSIC84.1.2.4.3 range B. also IEEE Standard 141.)

5.2.6 Deviations from rated line frequency and/or combinations of deviations of line frequency and voltagemay result in unsatisfactory drive operation. These conditions should be reviewed based on the typeof drive used.

5.2.7 Motor Time Ratlngs

Unless otherwise specified by the crane manufacturero the minimum motor1íme rating shall be inaccordance with Table 5.2.7-1.

55

Page 57: CMAA 70

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Page 58: CMAA 70

5.2.8 Squlrrel cage motors shall have high startlng torque, low starting current and h91 slip at tull load, similarfo NEMA Design D, unJess otherwise specified by the crane manufacturero

5.2.9 Motor size selection: The motor size selection involves torque and thermal considerations.

5.2.9.1 The motor rating of any drive, hoist or horizontal travel, using either AC or DC power, is basically fhe

mechanical horsepower with considerations for the effect of control, ambient temperatura, and serviceclass.

5.2.9.1.1 Holst Drlves

5.2.9.1.1.1 Mechanical Horsepower

Mechanical HP = W x V

33000 x E

W = total weight in pounds to be litted by the hoist drive rape system. This includes all items applicable

to the hoist such as the purchaser's Jifted load, which includes purchaserfumished attachmentsand crane manufacturers furnished items including the hook block and attachments.

V= specified speed in feet par minute when fitting weight W

."~, E = mechanical efficiency between the load and the motor, expressed in decimal form, where:K:'.

~::"-' E = (Eg)" x (E.)m

E = efficiency per gear reduction.g

n = number of gear reductions.

E. = rape system efficiency par rotating sheave.

m = the number of rotating sheaves between drum and equalizer passed ayer by each part of the

moving rape attached to the drum.

TABLE 5.2.9.1.1.1-1

Typical Efficiency Values

Bearings Eg* E.

Anti-friction .97 .99.r' SJeeve .93 .98\.,

* Note: The values of gear efficiency shown apply primarily to spur, herringbone, and helical gearing,

and are not intended for special cases such as worm gearing.

Reduction of E by ..02 is recommended for grease lubricated gearing.g

~,.

57

Page 59: CMAA 70

HOtST MECHANICAL EFFlClENCV '~II_-c

The tabulated values of overall hoist mechanical efficiency, E, as defined for anti-friction shea' t,

bearings are show in the following Table 5.2.9.1.1.1-2.

TABLE 5.2.8.1.1.1.2

HOIST OVERALL MECHANICAL EFFICIENCY

..Overall CombinedTotal Number of Total Number Efflclency of Efficie E

Ropes Supporting of Rotating Ropes Only 2 ear .3 GearOne Hook Block Sheaves for {Es>m Reductions Reductions

Each Rope 2 3Double Single Off Drum ftI n-n -

Reeved Reeved m .99 (El)" -.9409 {

4 2 1 .990 .931 .9036 3 2 .980 .922 .8948 4 3 .970 .913 .885

10 5 4 .960 .904 .87712 6 5 .951 .895 .86814 7 6 .941 .886 .85916 8 7 .932 .877 .85018 9 8 .922 .868 .84220 10 9 .913 .859 .834 A22 11 10 .904 .851 .825.24 12 11 .895 .842 .81726 13 12 .886 .834 .80928 14 13 .877 .826 .80130 15 14 .869 .817 .79332 16 15 .860 .809 .78534 17 16 .851 .801 .77736 18 11 .843 .793 .76938 19 18 .834 .785 .76140 20 19 .826 .m .75442 21 20 .818 .169 .746

5.2.9.1.1.2 Required Motor Horsepower

The hoist motor shall be selected 50 that its horsepower rating should not be less than that given by the

following formula:

Required rated horsepower = Mechanical horsepower x Kc

where K = Control factor, which is a correction value that accounts for the effects the controCs onc

motor torque and speed.

K = 1 for the majority of controls such as AC wound rotar magnetic, inverter, or static systems wherec there are no secondary permanent slip resistors, systems for squirrel cage motors, and constant

potential magnetic systems with DC power supplies.

For AC wound rotar systems, magnetic or sta tic control, with secondary permanent slip resistors.

Kc = motor rated fullload rpm*motor operating rpm, when hoisting

* At rated torque with permanent slip resistors

K values for power supplies rectified on the crane, for use with DC motors, magnetic or static controlcsystems, shall be determined by consultation with the motor and control manufacturers.

58

.

k.

Page 60: CMAA 70

~

The methods described far hoist motor~ epower selection are recornmended for use through CMMClass D. For Classes E and F, due consKjeration shall also be given to the thermaJ effects caused by

.the service. For example, this may require larger trame, largar horsepower, torced cooling, etc.

Latitude is permitted in selecting the nearest rated motor horsepower, ayer or under the requiredhorsepower, to utilize commercially available motors. In either case, due consideration must be givento proper performance of the drive.

5.2.9.1.2 Bridge and Trolley Drives

5.2.9.1.2.1 Indoor Cranes: Bridge and Trolley

ReQuired Motor Horsepower:

The travel motor shall be selected so that the horsepower rating is not less than that given by thefollowing formula:

HP = K xWxVxK..K. = acceleration factor for type of motor usedK. = service factor which accounts for the type of drive and duty cycle.

For reference see Table 5.2.9.1.2.1-EW = total weight to be moved including all dead and live loads (tons)V = rated drive speed (fpm)

For the general case of bridge and trolley drives:

f + 2000a x C,

K = gxEx~.33,000 x ~ N,

f = rolling friction of drive (including transmission losses) in pounds per ton (Ref. Table

5.2.9.1.2.1-0)a = average or eQuivalent uniform acceleration rafe in feet per second per second up to rated

motor rpm. For guidance, see Table 5.2.9.1.2. 1-A and Table 5.2.9.1.2.1-8C = rotational inertia factor.

r

= WK2 of crane & load + WK2 of rotating mass

WK2 of crane & load

or 1.05 + (a/7 .5) if WK2 is unknown

9 = 32.2 leer per second per second.E = mechanical efficiency of drive machinery expressed as a per unir decimal. (suggest use of

.9 if efficiency is unknown).Nr = rated speed of motor in rpm at fullload.Nf = free running rpm of motor when driving at speed V (see algo Section 5.2.10.2)~ = equivalent steady state torque relative to rated motor torque which results in accelerating up

to rated motor rpm (N,) in the same time as the actual variable torQue speed characteristk=of the motor and control characteristic used. See Table 5.2.9.1.2.1-C for typical values of Kr

-

59

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Page 61: CMAA 70

TABLE S.2.9.1.2.1-AGUIDE FOR TRA VEL MOTlON

TYPICAL ACCELERATlON RATES RANGE'

Free Running a -AccelerationRete in

FuI! Load Speed Feet per Sec. per Sec.Ft. per Min. Ft. per Seco for AC or DC2 Motora

60 1.0 .25 Min.120 2.0 .25 -.80180 3.0 .30 -1.0240 4.0 .40 -1.0300 5.0 .50 -1.1360 6.0 .60 -1.1 ..420 7.0 .70 -1.2 i.'"~'!;i;y'\.'", ",1"

480 8.0 .80 -1.3540 9.0 .90 -1.4600 10.0 1.0 -1.6

'The actual acceleration rates shall be selected for proper perfonnance including such items asacceleration time, free running time, motor and resistor heating, duty cycie,load spotting capability, andhook swing. The acceleration rate shall not exceed the values shown in Table 5.2.9.1.2. 1-B to awid

wheel skidding.

2For DC series motors the acceleration rate 'a' is the value occuring while on series resistors. ~'OUldbe in the range of 50 to 80 percent of the free running speed (NJ.

TABLE 5.2.9.1.2.1-8GUIDE FOR MAXIMUM ACCELERATION RATE TO PREVENT WHEEL SKIDDING

Percent of Driven Wheels 100 50 33.33 25 16.67

Maximum Acceleration RateFeet per Seco per Sec. .DryRails -Based on .2 Coefficient 4.8 2.4 1.6 1.2 .8

of Friction

Acceleration Rate-Wet Rai.ls. -Based on 2.9 1.5 1.0 .7 .5.12 CoeHlclentof Friction

rTABLE 5.2.9.1.2.1-C

RECOMMENDED V ALUES OF ~ (ACCELERA TING TORQUE FACTOR)

Type of Motor Type of Control 3K,

AC Wound Rotor Contactor-Resistor 1.3-1.5-AC Wound Rotor Static Stepless 1.3-1.5-

AC Wound Rotor, Mili Contactor-Resistor 1.5-1.7-AC Sq Cage Ballast Resistor 1 ~AC Induction Inverter 1.5DC Shunt Wound Adjustable Voltage 1.5

DC Series Wound Contactor-Resistor 2.0

3Kt is a function of control and/or resistor designo4Low end of range is recommended when permanent slip resistance is used.

60.~

Page 62: CMAA 70

TABLE 5.2.1.1.2.1-0

SUGGESTED VAlUES FOR F (FRICTlON FACTOR) FOR BRIDGES Ir TROllEYS

WITH MET AlUC WHEElS Ir ANTI-FRICTION BEARINGS

Wheel Dia.Inches 36 30 27 24 21 18 15 12 10 8 6

F rictionLbfTon(f) 10 10 12 12 12 15 15 15 15 16 16

Notes:-For cranes equipped with sleeve bearings of normal proportions, a friction factor of 24 pounds

per ton may be used.

-The above friction factors may require modifications for other variables such as low efficienqworm gearing, non-metallic wheels, special bearings, and unusual rail conditions.

TABlE 5.2.9.1.2.1-ERECOMMENDED VAlUES OF TRAVEl DRIVE SERVICE CLASS FACTOR'K .

DC Constant PotentlaJ AC Inverter AC Static withCMAA w/AlSE Series Mili Mtrs4 AC Ma netlc flxed Secondary

Service Adjustable Voltage ResistanceClass 60 Minutes 30 Minutes with DC Shunt Motors (Permanent Slip)

A .75 1.0 1.0 1.2B .75 1.0 1.0 1.2C .75 1.0 1.0 1.2D .85 1.15 1.1 1.3E' 1.0 N/A 1.2 1.4F2 1.4 N/A 1.4 1.6

IThe recommended values shown for Class E are based on a maximum of 30 percent time on and amaximum of 25 cycles per hour of the drive. A cycle for a bridge or trolley consists of two (2) moves (one(1) loaded and one (1) unloaded). For drive duty higher than this basis, it is recommended that duty cycle

methods of analysis be used.

2The recommended values shown for Class F are based on a maximum of 50 percent time on and amaximum of 45 cycles per hour of the drive. A cycle for a bridge or trolley consists of two (2) moves (one

(1) loaded and one (1) unloaded). Fordrive duty higherthanthis basis, itis recommendedthatdutycyde

methods of analysis be used.

3For recommended values of K for controls not shown, consult crane manufactureroa

4For industrial type DC motors, consult crane manufacturero

5.2.9.1.2.2 Latitude is permitted in selecting the nearest rated motor horsepower ayer or under, the requiredhorsepower to utilize commercially available motors. In either case, consideration must be given to

proper performance of the drive.

_Outdoor Cranes: Bridge drive motor horsepower for outdoor cranes.

61

Page 63: CMAA 70

5.2.9.1.2.3.1 Compute the free running bridge motor horsepower (HP F) at rated load and rated speed. neglecting anwind load, using the following formula:

HP -\,.,1 v \1 v fF -yy" y " I

33000

where W = fullload weight to be accelerated (tons)

V = fullload speed (fpm)

f = friction factor (pounds par ton) per Table 5.2.9.1.2.1-0

5.2.9.1.2.3.2 Compute the free running bridge motor horsepower due to wind force only (HP w) using the followin~formula:

HP = P x wind ares x Vw33000 x E

where: P = wind pressure (pounds par square foot) computed from the formula P = .OO256(V )2where V w is the wind velocity (mph). w

when V w is unspecified, P = 5 pounds per square foot should be used.

Wind ares = effective crane surface area exposed to wind in square feet as computed in s..~

3.3.2.1.2.1

V = fu/lload speed (fpm).

E = bridge drive mechanical efficiency.

5.2.9.1.2.3.3 The bridge drive motor horsepower sha/l be selected so that its horsepower rating should not be lessthan given by the following formula:

Required motor horsepower = 0.75 (HP F + HP w) K.

using HP F and HP w as computed above.where: K. = service class factor utilized per T able 5.2.9.1.2. 1-E

5.2.9.1.2.3.4 The fo/lowing items must be considered in the overa/l bridge drive design to assure proper operationunder all specified load and wind conditions:

a. Proper speed control, acceleration and braking without wind. r

b. Ability of control to reach fu/l speed mode of operation against wind.

c. Bridge speed. on any control point, when traveling with the wind not to exceed the amount resultingin the maximum safe speed of the brídge drive machinery.

d. Avoidance of wheel skidding which could likely occur under no load, low percent driven wheels andwind conditions.

e. Sufficient braking means to maintain the bridge braking requirements as defined in Section 4.9.4.

5.2.9.1.2.4 Outdoor Cranes: Tro/ley drive motor horsepower shall use same selection procedure as indoor cranesper section 5.2.9.1.2.1.

5.2.10 The gear ratio should be selected to províde the specified drive speed with rated load on the hook, forthe actual system used.

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5.2.10.1 Hoist Drtve Gear Ratlo

Hoist drive gear ratio = Nf x D x '7t

RxVx12

where: ~ = free running motor rpm when hoisting rated IDad W (lbs) at speed V (fpm). The value

~ is established from the motor-control speed-torque curves at the fullload hoisting

(HP Fl)'

HP Fl = W X V

33000 x E

E = mechanical efficiency per 5.2.9.1.1.1.D = drum pitch diameter (inches)V = specified fullload hoisting speed (fpm)R = rape reduction ratio = total number of rapes

supportinQ the load bk>Cknumber of rapes from the drum(s)

5.2.10.2 Travel Drlve Gear Ratios-Bridge and Trolley

Bridge or trolley drive gear ratio = Nf x Dw x 1t

r", V x 12

l.'"~ = free running rpm of the motor, alter the drive has accelerated, with rated load to the

steady state speed V. The value of N, is established from the motor-control speed-torquecurves at the free running horsepower (HP FA)'

HPFA = WxfxV

33000

where: W = totaliDad (tons).f = rolling friction (pounds per ton) per Table 5.2.9.1.2.1-DV = specified fullload travel drive speed (fpm).D = wheel tread diameter (inches)..

5.2.10.3 Variations from the calculated gear ratio is permissible to facilitate the use of standard available ratios,provided that motor heating and operational performance is not adverseiy affected. The actual fullloaddrive speed may vary a maximum of :t1 O percent of the specified fullload speed.

5.3 BRAKES

,..5.3.1 Types of electrical brakes for hoist and traverse motions shall be specified by the crane manufacturero

5.3.2 Refer to Section 4.9 of this specification for brake selection and rating.

5.3.3 Holding brakes shall be applied automatically when power to the brake is removed.

5.3.4 On hoists equipped with two electric holding brakes, a time delay setting of one brake may be included.

5.3.5 On direct current shunt brakes, it may be desirable to include a forcing circuit to provide rapid settingand release.

5.3.6 Brake coil time rating shall be selected for the duration and frequency of operation required by theservice. Any electrical traverse drive brake used only for emergency stop on power loss or setting byoperator choice shall have a coil rated for continuous duty.

5.3.7 Brake for the trolley is recommended with use of an inverter when proper braking and three phasemonitoring is not provided in the VFD.

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~~IIIIIIII

5.4 CONTROLLERS, AL TERNA TINO ANO DIRECT CURRENT 11111- ~I I -5.4.1 Scope- This section covers requirements for selecting and controlling the direction, speed, acceler,

'1 ; tion and electrical braking of the crane hoist and travej motors. Other control requirements such a

protection and master switches are covered in other sections.

5.4.2 On cranes with a combination of cab with master switd1es, and pendant floor control, the applicabl'specifications for cab controlled cranes shall apply. On fk>or operated cranes where the pendant maste

: is al so used in a "skeleton" cab, the applicable speciOCations for floor controlled cranes shall apply. 1

,: 5.4.3 On remate controlled cranes, such as by radio or carrier signal the applicable floor control specification ;1...

shall apply, unless otherwise specified. ¡,

t

5.4.4 Control systems may be manual, magnetic, static, inverter (variable frequency) or variable voltage DCor in combination as specified.

; 5.4.4.1 Hoists shall be fumished with a control braking means, either mechanicaJ or power. Typical mechanica

means include mechanical load brakes or self-locking worm drives. Typical power means includf Idynamic lowering, eddy-current braking, counter-torque, and regenerative braking.

~5.4.4.2 Bridge and Trolley Travel

With the exception of floor operated pendant control class A, B & C cranes, sIl bridges and troll~..shallbe furnished with reversing control systems incorporating plugging protection. Typical ~,"dgingprotection include a magnetic plugging contactar, ballast resistors, slip couplings, motorcharacteristics,or static controlled torque.

5.4.5 Magnetic Control

5.4.5.1 Each magnetic control shall have contactors of a size and quantity for starting, accelerating, reversing.and stopping, and for the specified CMAA crane service class. AII reversing contactors shall bemechanically and electrically interlocked.

5.4.5.2 The minimum NEMA size of magnetic contactors shall be in accordance with Tables 5.4.5.2-1 ACWound Rotor, 5.4.5.2-2 AC Squirrel Cage, and 5.4.5.2-3 DC. Definite purpose contactors specificallyrated for crane and hoist duty service may be used for CMAA crane service classes A, B, and C providedthe application does not exceed the contactar manutacturer's published ratings. lEC Contactors maybe used for Crane and Hoist duty service provided the application does not exceed the contactar

manufacturer's published ratings.TABLE 5.4.5.2-1

AC CONT ACTOR RA TINGS FOR WOUND ROTOR MOTORS8-hour Maximum Intermittent Ratin ** r '

Size of Open Rating, Horsepower atContactar Amperes Amperes* 460 and

2 7 V /tO 20 20: 3 51 30 30 I 71/2 10

2 50 67 20 403 100 133 40 804 150 200 63 1255 300 400 150 3006 600 800 , 300 -6007 900 1200 450 9008 1350 1800 600 1200

*The ultimate trip current of overload (overcurrent) relays or other motor protective devices used shall ¡not exceed 115 percent ofthese values or 125 percent ofthe motorfull 'Dad current. whichever is smaller. \

** Wound rotar primary contactors shall be selected to be not less than the current and horsepower ratings.

Wound rotar secondary contactors shall be selected to be not less than the motor fullload secondarycurrent, using contactar intermittent rating. The ampere intermittent rating of a three paje secondary

64 contactar with pajes in delta shall be 1-1/2 times its wound rotar intermittent rating.

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'TABLE 5.4.5.2-2

AC CONTACTOR RATINGS FOR SQUIRREL CAGE MOTORSMAXIMUM INTERMITTENT HORSEPOWER RATING

Size of 230 460 & 575Contactor Volts Volts

O 3 51 71h 102 15 25.3 30 .SO'

*Squirrel cage motors over 20 horsepower are not normally used for crane motions.

TABLE 5.4.5.2-3

DC CONT ACTOR RA TINGS FOR 230 VO.L T CONTROLS*.

8-hour Maximum Intermittent Rating

Slze of Open Rating,Contactor Amperes Amperes Horsepower

1 25 30 71h2 50 67 153 100 133 354 150 200 555 300 400 1106 600 800 2257. 900 1200 3308. 1350 1800 5009. 2500 3330 1000

*Resistor stepping contactors may be rated for the actual current carried.

**For constant potential DC drives other than 230 to 250 volts, refer to NEMA ICS 8 part 3 Table 3-4-1.

For adjustable voltage DC drives at voltage other than 230 volts, the contactar horsepower ratings will

be directly proportional to the voltage up to a maximum of 600 volts.

5.4.5.3 The minimum number of resistor stepping contactors, time delay devices and speed points for AC

wound rotar motors and DC motors shall be shown in Table 5.4.5.3-1.

~

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'.. ~ MINIMUM NUMS;::F T ::S~:=P~~~~!::.TIME DELA Y DEVICES AND SPEED POINTS FOR MAGNETIC CONTROLS

MIN. NO. OF MIN. NO. OF MIN. NO. OFRESISTOR STEPPING TIME DELA y SPEED POINTSCONTACTORS D~ES

HORSEPOWER (See Note 1) (See Note 2) (See Note 3)

CMAA CLASS CMM CLASS CMAA CLASS

A,B C D,E,F A,B C D,E,F A,B C D,E,

FOR AC WOUND ROTOR SECONDARY RESISTORSCAB CONTROL CRANES

Less than 8 28 3 3 1 2 2 3 4 48 thru 15 3 3 3 1 2 2 4 4 416 thru 30 38 4 4 1 3 3 4 5 531 thru 75 4 4 4 1 3 3 5 5 576 thru 125 5 5 5 1 4 4 6 6 6126 thru 200 5 5 5 4 4 4 6 6 6Greater than 200 6 6 6 5 5 5 7 7 7

FOR AC WOUND ROTOR SECONDARY RESISTORFLOOR CONTROL CRANES

Less than 30 2 2 3 1 1Greater than 30 Same as for cab control cranes

FOR DC MOTOR SERIES RESISTORS @.230 VOLTSCAB CONTROL CRANES

Less than 8 3 3 3 1 2 2 4 4 48 thru 15 3 4 4 1 388 388 4 5 516thru35 3 4 4 1 388388 4 5 536 thru 55 3 4 4 1 388 388 4 5 556thru110 4 4 4 388 388 388 5 5 5Greater than 110 5 5 5 488 488 488 6 6 6

FOR DC MOTOR SERIES RESISTORS @230 VOLTSFLOOR CONTROL CAANES

O thru 15 2 2 3 1 1 2 3 3 416 thru 30 3 3 4 2 2 3 4 4 5Greater than 30 Same as for cab control cranes

Notes to Table continue on next page.

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Foot Not88 to Table 5.4.5.3-1 I~i -

*A 10 percent slip resistance or one (1) additional contactar shall be provided on bridge and trolleydrives.

**Numbers shown apply to bridge and trolley drives. For hoists, a minimum of two (2) time delay devicesare required in the hoisting direction.

Note 1: One (1) contactar of the number shown may be used for plugging on bridge or trolley controlsor low torque on hoist controls.

If more than one (1) plugging step is used, additional contactors may be required.

Note 2: Plugging detection means shall be added to prevent closure of the plugging contactors until thebridge or trolley drive has reached approximately zero speed.

Note 3: A speed point may be manual hand controlled, or automatic, as required.

The minimum number of operator station hand controlled speed points shall be three (3) in eachdirection except as follows:

(a) Class C,D,E and F, cab operated hoist controllers with tour (4) or more resistorstepping contactorsshall haya a minimum of five (5) hand controlled speed points in each direction.

(b) Class A and B, controllers for AC wound rotar motors less than 8 horsepower shall have a minimumot two (2) hand controlled speed points in each direction.

(c) Controllers for floor operated bridge and trolley motions shall ha ve a mínimum of one (1) handcontrolled speed point in each direction.

(d) When specified, a drift point (no motor power, brake released) shall be included as a hand controlledspeed point in addition to the above minimum requirements for bridge and trolley motions.

.5.4 On multi-motor drives, the contactar requirements of this section apply to each motor individually, exceptif one set of line reversing contactors is used for sIl motors in parallel, then the line contactors shall besized for the sum of the individual horsepowers. The resistor stepping contactors may be common multi-paje devices, if desired. An individual set of acceleration resistors for each motor shall be providedunless otherwise specified. Timing shall be done with one (1) set of time delay devices.

6 Static Control,

6.1 Static power components such as rectifiers. reactors. resistors, etc.. as required, shall be sized with dueconsideration of the motor ratings, drive requirements, service class. duty cycle. and application in thecontrol.

5.4.6.2 Magnetic contactors. if used. shall be rated in accordance with Section 5.4.5.2.

5.4.6.3 Static control systems may be regulated or non-regulated. providing stepped or stepless control usingAC or DC motors. as specified.

5.4.6.4 Travel drives systems may be speed and/or torque regulated, as specified. If a speed regulated systemis selected the method of deceleration to a slower speed may be by drive friction or drive torque reversal,as specified. Hoist drives are assumed to be inherently speed regulated and due consideration shall begiven to the available speed range, the degree of speed regulation, and optionalload float.

Primary reversing of AC motor drives shall be accomplished with magnetic contactors or staticcomponents as specified. When static components are used, a line contactar shall be fumished for the

drive.

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5.4.6.6 Current and torque limiting provisions shall be included not to exceed the motor design limitations, anwith consideration for desired acceJeration,

5.4.6.7 Control torque plugging provisions shall be included for bridge or trolley drives.

5.4.6.8 Permanent slip resistance may be included providing due consideration is given to the actual motcspeeds under rated conditions.

5.4.6.9 The crane specifications shall state whether the hoist motor horsepower used with static control is othe basis of average hoisting and lowering speed with rated load or on the basis of actual hoisting speeto raise rated loado

5.4.7 Enclosures

5.4.7.1 Control panels should be enclosed and shall be suitable for the environment and type of control. Th(type of enclosure shall be determined by agreement between the purchaser and the crane manufacturer. A typical non-ventilated enclosure may be in accordance with one of the following NEM.t8tandards publication IC86 classifications:

ENCLOSURES FOR NON-HAZARDOUS LOCA TIONSType 1 -General purpose-lndoor.Type 1A -General purpose-lndoor-Gasketed.

(Note: Type 1-A enclosure is not currently recognized by NEMA) 6Type 2 -Dripproof-lndoor. .;'Type 3 -Dusttight, raintight and sleet-resistant, ice-resistant-Outdoor.Type 3R -Rainproof and sleet-resistant, ice-resistant-Outdoor.Type 38 -Dusttight, raintight and sleet (Ice-) proof-Outdoor.Type 4 -Watertight and dusttight-lndoor and Outdoor.Type 4x -Watertight, dusttight and corrosion-resistant-lndoor and Outdoor.Type 12 -Industrial Use-Dusttight and driptight-lndoor.Type 13 -Oiltight and dusttight-lndoor.

ENCLOSURES FOR HAZARDOUS LOCA TIONSType 7 -Glass 1, Division 1, Group A, B, C, or D-lndoor Hazardous Locations-Air-break

Equipment.Type 9 -Glass 11, Division 1, Group E, F, or G-lndoor Hazardous Locations-Air-break Equipment.

5.4.7.2 Enclosures containing devices that produce excessive heat or ozone or devices that require cooling for

proper operation. may require ventilation means. These enclosures shall be equipped with thenecessary ventilation such as louvers or torced cooling. Air filters or similar devices may be necessarydepending on the environment. Since the original definition of the enclosure per its specified typA maybe somewhat altered by the nature of the ventilation means, the final design shall meet the ni )nalintento

5.4.7.3 Unless otherwise specified, enclosures for electrical equipment other than controls shall be suitable forthe environment, and in accordance with the following practices.:

(a) Auxiliary devices such as safety switches, junction boxes, transformers, pendant masters, lightingpanels, main line disconnects, accessory drive controls, brake rectifier panels, limit switches, etc" maybe supplied in enclosures other than specified for the control panel,

(b) Resistor covers for indoor cranes, jf required to prevent accidentaf-contact under normal operatingconditions, shall ínclude necessary screening and ventilation. Resistor covers for outdoor cranes shallbe adequately ventilated.

c) Brake covers:1. Brakes, for indoor cranes, may be supplied without covers.2. Brakes, for outdoor cranes, shall be supplied with covers.

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.5.5 RESISTORS ;-

.5.5.1 Resistors (except those in permanent sections) shall have a thermal capacity of oot less than NEMAClass 150 series for CMAA crane service classes A, B and C and not less than NEMA Class 160 seriesfor CMAA service classes D. E. and F.

5.5.2 Resistors used with power electrical braking systems on AC hoists not equipped with mechanicalloadbrakes shall have a thermal capacity of not less than NEMA Class 160 series.

5.5.3 Resistors shall be designed to provide the proper speed and torque as required by the control systemused.

5.5.4 Resistors shall be installed with adequate ventilation, and with proper supports to withstand vibrationand to prevent broken parts or molten metal falling from the crane.

5.6 PROTECTlON ANO SAFETY FEA TURES

5.6.1 A crane disconnecting means, either a current-rated circuit breaker or motor rated switch, lockable inthe open position, shall be provided in the leads from the runway contact conductors or other powersupply.

5.6.2 The continuous current rating of the switch or circuit breaker in Section 5.6.1 shall not be less than50 percent of the combined short time motor fullload currents, nor less than 75 percent of the sum ofthe short time fullload currents of the motors required for any single crane motion, plus any additionaJloads fed by the device.

5.6.3 The disconnecting means in Section 5.6.1 shall have an opening means located where it is readilyaccessible to the operator's station, or a mainline contactar connected after the device in Section 5.6.1may be furnished and shall be operable from the operator's station.

5.6.4 Power circuit fault protection devices shall be fumished in accordance with NEC Sections 110-9Interrupting Rating. The user shall state the available fault current or the crane manufacturer shall statein the specification the interrupting rating being furnished.

5.6.5 Branch circuit protection shall be provided par NEC Section 610-42 Branch Circuit Protection. !

5.6.6 Magnetic Mainline contactors. when used, shall be as shown in Tables 5.6.6-1 and 5.6.6-2. The sizeshall not be less than the rating of the largest primary contactar used on any one motion.

.,~'JW!

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TAa! ,AC CONTACTOR RATINGS

fo, Malnllne Servlc.

8-hour Maxlmum Maxim Maximum HorsepowerSize of Open ratlng Intermittent Motor Ho for any Motion

Contactars Amperes Duty Rati~g 460 &Amperes 230V 230V 575V

O 20 20 8 8 3 51 30 30 10 20 7Yl 102 50 87 30 60 20 403 100 133 83 125 40 804 150 200 110 225 83 1255 300 400 225 450 150 3006 600 800 450 900 300 8007 900 1200 675 1350 450 9008 1350 1600 900 1600 800 1200

eThe ultimate trip current af overlaad (overcurrent) relays or other motor protective devices usedshall not exceed 115 percent of these values or 125 percent of the motor fullload current, whlcheveris smaller.

TABLE 5.8.8-2

RATINGS AT 230 to 250 VOLTS OF DCCONTACTORS

for Maln"n. S.rvlc.

8-hour Maxlmum. .Size of Ope ti Intermlttent Maxlmum Total Maxlmum Horsepower

n ra ngContactars Amperes Duty Ratlng Motor Horsepower for any Motlon

Amperes

1 25 30 10 71h2 50 67 22 153 100 133 55 354 150 200 80 555 300 400 160 1106 800 800 320 2257 900 1200 480 3308 1350 1800 725 5009 2500 3330 --r

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5.6.7 Motor running overcurrent protection shall be provided in accordance with NEC 610-43 Motor Running

Overload Protection.

5.6.8 Control circuits shall be protected in accordance with NEC 610-53 overcurrent protection.

5.6.9 Undervoltage protection shall be provided as a function of each motor controller, or an enclosed

protective panel, or a magnetic mainline contactor, or a manual-magnetic disconnect switch.

5.6.10 An automatically reset instantaneous trip overload relay set at approximately 200 percent 01 the hoistmotor full load current shall be fumished for DC hoists. Devices offering equivalent motor torquelimitation may be used in lieu of the overfoad relay.

5.6.11 Cranes not equipped with spring-retum controllers, spring-retum master switches, or momentarycontact pushbuttons, shall be provided with a device which will disconnect sIl motors from the line onfailure of power and will not permit any motor to be restarted until the controller handle is brought to the'off' position, or a reset switch or button is operated.

5.6.12 Remote radio cranes shall be provided with a permissive radio signar in addition to a crane motion radiosignal, and both signals shall be present in order to start and maintain a crane motion.

5.6.13 On automatic cranes, all motions shall be discontinued if the crane does not operate in accordance withthe automatic sequence of operation.

(5.6.14 Working space dimensions shall apply only to bridge mounted control panel enclosures or switching-'-- devices that are serviceable from a crane mounted walkway. The horizontal distance from the surface

of the enclosure door to the nearest metallic or other obstruction shall be a minimum of 30 inches. Inaddition, the work space in front of the enclosure shall be at least as wide as the enclosure and shall notbe less than 30 inches wide.

5.6.15 Warning Devlces

5.6.15.1 Except forfloor-operated cranes a gong or othereffective warning signal shall be provided for each craneequipped with a power traveling mechanism.

5.6.15.2 Owner or Specifier, having full knowledge of the environment in which the crane will be operated, isresponsible for the adequacy of the warning devices.

5.7 MASTER SWITCH ES

5.7.1 Cab controlled cranes shall be fumished with master switches for hoist, trolley and bridge motions, asapplicable, that are located within reach of the operator. -

( 5.7.2 Cab master switches shall be provided with a notch, or spring retum arrangement latch, which, in the'off' position prevents the handle from being inadvertently moved to the 'on' position.

5.7.3 The movement of each master switch handle should be in the same general direction as the resultantmovement of the load, except as shown in Figures 5.7.3a and 5.7 .3b, unless otherwise specified.

5.7.4 The arrangement of master switch es should conform to Figures 5.7 .3a and 5.7 .3b, unless otherwise

specified.

5.7.5 The arrangement of other master switches, lever switches or pushbuttons for controller, other than hoist,trolley or bridge. (such as grabs, magnetic disconnects, turntables, etc.) are normally specified by themanufacturer.

5.7.6 If a master switch is provided for a magnet controller, the 'Iift' direction shall be toward the operator andthe 'drop' direction away from the operator.

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.

Bridge Drive Girder8ndg8 A-

:;: ltlf!t!i ~ :e~ M._'" ~-.o-.. ~ -.o-.a~ A.- ~ '1 ...0Ao

-.o.- ~~ o-.

Left-Hand Cab Right-Hand Cab

Center Cab

4 Motor Crane

RECOMMENDED ARRANGEMENT OF CONTROLLERS .~

Fig. 5.7.38

Bridge Drive Girder

:;: ,1,1 !1 ..~e ~ M -¡ ¡ ¡ .., ~~

~;~ ...o-.~ ~ ~ ~ f?2?; ~

w~ +-0-+

Left-hand Cab Right-Hand Cab

Center Cab

3 Motor Crane

RECOMMENDED ARRANGEMENT OF CONTROLLERS

Fig. 5.7.3b

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Page 74: CMAA 70

.5:7.7 Cranes fumished with skeleton (dummy) cabs are to be operated vis the pendant pushbutton station arKjthereby do not require master switches unless otherwise specified by the purchaser.

5.7.8 Master switches shall be clearfy labeled to indica te their 1unctions.

5.8 FLOOR OPERA TED PENDANT PUSHBUTTON SrA TlONS

5.8.1 The arrangement of pendant pushbutton stations should conform to Figure 5.8.1 unless otherwiseagreed between the manufacturer and owner.

5.8.2 Pushbuttons shall retum to the .off. position when pressur is released by the crane operator.

5.8.3 Pendant pushbutton stations shall have a grounding conductor between a ground terminal in the statiooand the crane.

5.8.4 The maximum voltage in pendant pushbutton stations shall be 150 Volts AC or 300 Volts DC.

5.8.5 Pushbuttons shall be guardad or shrouded to prevent accidental actuation of crane motions.

5.8.6 .Stop. pushbuttons shall be colo red red.

5.8.7 Pendant pushbutton station enclosures shall be defined in Section 5.4.7 .3(a).

(~:.. 5.8.8 Pendant pushbutton stations shall be supported in a manner that will protect the electrical conductorsagainst strain.

5.8.9 Minimum wire size 01 multiconductor flexible cords for pendant pushbutton stations shall be #16 AWGunless otherwise permitted by Article 610 of the National Electrical Codeo

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,.

FIGURE 5.8.1 ,;

PENDANT PUSHBUTTON STATION ARRANGEMENT

In each user location, the relative arrangement of units on crane pendant pushbuttonstations should be standardized. In the absence of such standardization, suggestedarrangement is shown in Figure 5.8.1.

OPowerOn I

OPowerOft

O IJ¿.'.~Up

ODown

Maln Hoiet

OUp

ODown

Aux. HoIat

ORight (

OL8ft

Troney

OForward

T- OReYerM

Bridge

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Page 76: CMAA 70

..1 UMIT SWITCHES

5.9.1 The hoist motion of a/l cranes sha/l be equipped with an overtravel limit switch in the raising directionto stop hoisting motion.

5.9.2 Interruption of the raising motion shall not intertere with the lowering motion. Lowering of the block shallautomatica/ly reset the limit switch unless otherwise specified.

5.9.3 The upper limit switch shall be power circuit type, control circuit type or as specified by the purchaser.The manufacturers proposal shall state which type is being furnished.

5.9.4 Lower limit switches shall be provided where the hook can be lowered beyond the rated hook travelunder normal operating conditions and shall be of the control circuit type.

5.9.5 Trolley travel and bridge travellimit switches, when specified sha/l be of the control circuit type.

5.9.6 The trip point of alllimit switches shall be located to allow 10r maximum runout distance of the motionbeing stopped for the braking system being usad.

5.10 INST ALLA TION

5.10.1 Electrical equipment shall be so located or enclosed to prevent the operatorlrom accidental contact with( live partS under normal operating conditions.

.5.10.2 Electrical equipment shall be installed in accessible locations and protected against ambient environ-mental conditions as agreed to by the purchaser and the crane manufacturar.

5.11 BRIDGE CONDUCTOR SYSTEMS

5.11.1 The bridge conductors may be bare hard drawn copper wire, hard copper, aluminum or steel in the formof stiff shapes, insulated cables, cable real pickup or other suitable means to meet the particularapplícation and shall be sized and installed in accordance with Article 61 O of the National Electrical Codeo

5.11.2 If local conditions require enclosed conductors, they must be specified by owner or specifier.

5.11.3 The crane manufacturer shall sta te the type conductors to be furnished.

5.11.4 The published crane intermittent ratings of manufactured conductor systems shall not be less than theampacity required for the circuit in which they are used.

5.11.5 Current collectors, if used. shall be compatible with the type of contact conductors lumished and shallbe rated for the ampacity of the circuit in which they are usedo Two (2) sets of current collectors shallbe furnished for sIl contact conductors that supply current to a lifting magneto

5.12 RUNW A y CONDUCTOR SYSTEMS

5.12.1 Refer to Section 1.5 01 70-1 General Specifications for information on runway conductors.

5.1202 Current collectors, if used, shall be compatible with the type 01 contact conductors fumished. Thecol lector rating shall be sized for the crane ampacity as computed by Article 610 of the Natíonal ElectricalCodeo A mínimum of two co/lectors for each runway conductor shall be lumished when the crane ís usedwith a lifting magneto

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5.13 VOL T AGE DROP

5.13.1 The purchaser shall fumish actual voltage at the runway conductor supply taps not more than 10E

percent and not less that 96 percent of the nominal system voltage, and shall define the requirementsof the runway conductor system to achieve an input voltage not less than 93 percent of the nominal

system voltage to the crane at the point of runway conductor co/lection farthest from the runwayconductor supply taps.

5.13.2 The crane manufacturer sha/llimit the voltage drops within the crane to the motors and other electricalloads to approximately 2 percent of the nominal system voltage.

5.13.3 AII voltage drops in Section 5.13.1 and 5.13.2 shall be computed by using main feeder currents,individual motor currents, fixed load currents, and demandfactors of multiple cranes on the same runwayas defined by Article 610 of the National Electrical Codeo

5.13.4 Voltage drops sha/l be calculated during maximum inrush (starting) conditions to insure that the motorterminal voltages are not less than 90 percent of rated motor voltage, and control and brake voltagesare not less than 85 percent of device rated voltage.

5.13.5 The actual operating voltages at the crane motor terminals sha/l not exceed 110 percent or not dropbelow 95 percent of motor ratings, for rated running conditions, to achieve the results defined in Section5.2.4 (voltage). --

5.14 INVERTERS (VARIABLE FREQUENCY DRIVES) ~~\

5.14.1 Inverter selection shall be based on the drive motor(s) output requirements as fo/lows:

kxKWInverter Output = $: Inverter Capacity in KVA

ExPF

Where: k = Inverter correction factor (1.05-1.1)KW = Required motor outputE = Motor efficiencyPF = Motor powerfactor

Inverter continuous current must be equal to or greater than fullload motor current.Inverter overload capacity = 1.5 x tull load motor current.

5.14.2 Inverter drives shall be provided with dynamic braking function or fu/ly regenerative capability. The

dynamic braking and inverter duty sha/l meet the requirements of the drives service class. -

5.14.3 Inverters shall be provided with proper branch circuit protection on the line side. (

5.14.4 Distorted waveforms on the line and/or short circuit current may require the use of isolation transformers,filler or line reactors.

5.14.5 Line contactar shall be used with inverters for hoisting applications to disconnect power from drive incase of overspeed or fault.

5.14.6 AII inverters shall have overspeed protection. Mechanicalload brake may be considered as overspeedprotection for hoisting motion. -

Dynamic braking resistors may be considered as overspeed protection for horizontal drives.

5.14.7 A minimum of two co/lectors for each runway conductor shall be furnished with inverter use. Use ofgrounding conductor is recommended.

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5.15 REMaTE CONTROL

5.15.1 Remote control may be by means 01 radio or infrared transmission or an off-crane control stationconnected to the crane through wiring. The control station may consist of pushbuttons, masterswitches,computer keyboards or combination thereof. For definition of remate control, see the applicable ANSI/ASME standards.

5.15.2 The selection and application of the remate control system should be done to assure compatibilitybetween the remate control and the crane control system and eliminate interference.

5.15.3 When more than one control station is provided, electrical interlocks shall be included in the system topermit operation from only one station at a time. Electrical interlock is defined as effective isolation ofthe control circuits with the use of rotary switch contacts, relay contacts or with the use of aprogrammable logic controller and its inpuVoutput modules.

5.15.4 Due consideration should be given to elimination of interference between electronic signals and powercircuits. This includes physical and electrical separation, shielding, etc.

5.15.5 Due consideration should algo be given to the following:a) Operating range of the remate control equipment.b) Operating speeds of the crane.c) Application of end travellimit switches.d) Wiring of magnet and vacuum circuits to the line side 01 the disconnecting means and use of latching

controls.

5.15.6 See Figure 5.15.6 10r traditional radio transmitter lever arrangement. Transmitter arrangements otherthan as shown (belly box style) may be used.

5.15.7 Power disconnecting circuits and warning device shall be provided.

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FIGURE 5.15.6

RADIO CRANE CONTROL TRANSMITTER LEVER ARRANGEMENT

4 Motion

Bridge Trolley Main Au~.Hoist Ho'8t

X y Down Down

W Z Up Up

~~3 Motion

Bridge Trolley Hoi8t

X y Down

W Z Up

(

~~NOTE:

.[ Markings o~ the crane, visible from the. floo~, shall indicate the direction of bridge and trolley travel

correspondlng to the W, X, Y and Z deslgnatlons on the transmltter.1

The letters used are only intended for the purpose of illustration.

Designations should be selected as appropriate to each installation.

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70-8 RECOMMENDED ~.Ate ItQU8RY DATA 8It&TFig. 8.1

.Customer

Spec No.

Date

---

1. Number Cranes Required .

2. Capaclty: Main Hoist Tons Aux. Hoist Tons Bridge Tons

3. Required Hook LIft (Max. Including Plts or Wefls Below Floor Elevatíon)

Maln Hoist Ft. In. Aux. Hoist Ft.ln.

4. Approximate Length of Runway Ft.

/'" 5. Number of Cranes on Runway .!

6. Service Information: C.M.A.A. Class (See Section 70-2)

Main Hoist: Average Uft Ft. Number of Llfts per Hour Speed fpm

Hours per Day Hook Magnet Bucket

Glve Size & Weight of Magnet or Bucket

Aux. Hoist: Average Uft Ft. Number of Llfts per Hour Speed fpm

Hours per Day Hook Magnet Bucket

Give Size & Weight of Magnet or Bucket

Bridge: Number Moves per Hour Hours per Day Speed fpm

Average Movement

Trolley: Number ~ Moves per Hour Hours per Day Speed fpm

Average Movement

7. Furnish complete information regardlng special conditions such as acid fumes, steam, hlgh temperatures, highaltitudes, excesslve dust or moisture, very severe duty, special or precise load handling:

8. Ambient Temperature in Building: Msx. Min.

9. Material Handled

10. Crane to Operate: Indoors Outdoors Both

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11. Power: VoIts Phase Henz A O. Volts DO

12. Method 01 Control: Cab Aoor Other -

13. Location ot Control: End ot Orane Center On Trolley

Other- -

14. Type ot Control (Give complete intormation. including number ot speed points) Ret. 5.4.4

Main Hoist

Auxiliary Hoist_-

Trolley

Bridge

15. Type ot Control Enclosure: (Ret. 5.4.7.1)-

16. Type ot Motors: (Give complete intormatlon)

17. ""SI winng comply w"h Spoc;o' Cond;';..s ., CodeS~)

Describe briefly (Se e Items 7 & 8)

18. Bridge Conductor Type:

19. Runway Conductor Type: Insulated (MFR)

Bare Wires Angles Other

Furnished By:

20. List ot Special Equipment or Accessories Desired .

(21. For special cranes with multiple hooks or trolley or other unique requirements. provide detailed intormationon hook spacing. orientation, capacities. and total bridge capacity.

22. Complete attached building clearance drawing. making special note ot any obstructions which may interferewith the crane, including special clearance conditions underneath the girders or cabo

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CLEARANCES: Complete th8 building dI b8Iow making lP8CI8I ~ of any obetructlonl ,Interfer8 wIth the crane kddng lpeCial clearance requlrement8 under gird818 ~ c8).

Low pcMnt of roo' truss. lights.t- H -i sprinkter. or other obstructions I f

T--ó -r

-1--A (Span-c to c of runway rails)Aall Size: O E

Cap Channel 5iz.8: A k-"+'"Runway Beam Slze: S -1-C;=:;: =:=i~ Runway / ~M N

B T ConductorsL Type:P Obstruction

i OperatingFloor

Plt Aoor

ELEVATION--

A H P

B I a

C J A

D K S

E L T

F M U

G N V

Indicate the "North" dlrection, cab or pendant location, relatlve locations ofmain and auxiliary hook, runway conductor location. adjacent cranes, etc.

A (Span-c to c of runway rails)

~ ~w w~ Idler Girder ("B" Girder) ~c c

.e.c .c

:: Centerllne of Hooks "'2 .E~ Yo .~.J I -= I IX:

.=IX: e>- Drive GirOSr ("A" Girder) IX:m >-

mI ~

~IX:

Waikway-if required

PLAN

81

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-,c;;,

Al- 1.18UGOESTEO OPERATlNO SPEEDS

FEET PEA MINUTEFLOOA CONTROLLED CRANES

CAPACITY HOIST TAOLLEY BRIDGEIN

TONS SLOW MEDIUM FAST SLOW MEDIUM FAST SLOW MEDlUM FAST

3 14 35 45 50 80 125 50 115 175

5 14 27 40 50 80 125 50 115 175

7.5 13 27 38 50 80 125 50 115 175

10 13 21 35 50 80 125 50 115 175

15 13 19 31 50 80 125 50 115 175

20 10 17 30 50 80 125 50 115 175

'25 8 14 29 50 80 125 50 115 175

30 7 14 28 50 80 125 50 115 150

35 7 12 25 50 80 125 50 115 150

40 7 12 25 40 70 100 40 100 150

50 5 11 20 40 70 100 40 100 150

60 5 9 18 40 70 100 40 75 125

75 4 9 15 40 70 100 30 75 125

100 4 8 13 :.) 60 80 25 50 100

150 3 6 11 25 60 80 25 50 100

NOTE: Consideration must be given to length of runway for the bridge speed, span of bridge fOl' the trolleyspeed, dlstance average travel, and spotting characterlstics required.

Fig. 6.3SUGGESTED OPERATINO SPEEDS

FEET PER MINUTECAB CONTROLLED CRANES

CAPACITY HOIST TROLLEY BRIDGE

INTONS SLOW MEDIUM FAST SLOW MEDIUM FAST SLOW MEDIUM FAST

3 14 35 45 125 150 200 200 300 400

5 14 27 40 125 150 200 200 300 400

7.5 13 27 38 125 150 200 200 300 400

10 13 21 35 125 150 200 200 300 400

15 13 19 31 125 150 200 200 300 400

20 10 17 30 125 150 200 200 300 400

25 8 14 29 100 150 175 200 300 400

30 7 14 28 100 125 175 150 250 350

35 7 12 25 100 125 150 150 250 350

40 7 12 25 100 125 150 150 250 350

50 5 11 20 75 125 150 100 200 ~

60 5 9 18 75 100 150 100 200 ~

75 4 9 15 50 100 125 75 150 200

100 4 8 13 50 100 125 50 100 150

150 3 6 11 30 75 100 50 75 100

NOTE: Consideration must be glven to length of runway for the bridge speed, span of bridge for the trolley

speed, distance average travel, and spotting characteristics requlred.

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-70-7 GLOSSARY ~~,

r ABNORMAL OPERATlNG CONDITIONS: Environ- CAB-oPERATED CRANE: A crane cootro/led by en

mental conditions that are unfavorable. ha nn fuI or operator in a cab located on the bridge or trol/ey.detrimental to or for the operation of a hoist, such asexcessively high (over 100 deg. F) or low (below O deg. CAMBER: The slight upward vertical curve given toF.) ambient temperatures, corrosive fumes, dust laden girders to compensate partial/y for deflection due toor moisture laden atmospheres, and hazardous loca- hook load and weight of the Crane.tions.

CAPACITY: The maximum rated load (in fans) whichI ADJUSTABLEORVARIABLEVOLTAGE: Amethod a crane is designed to handle.It~! of .control by which the motor supply voltage can be

adJusted. CLEARANCE: Minimum distance from the extremity

.of a crane to the nearest obstruction.AUTOMA TIC CRANE: A crane which when activatedoperates through a preset cycle or cycles. CMAA: Crane Manufacturers Associatioo of America,

Inc. (fonnerly EOCI-Electric Overhead Crane Insti-AUXILlARY HOIST: A supplemental hoisting unit, tute).

usually designed to handle lighter loads at a highersped than the main host. COLLECTORS: Contacting devices for co/lecting cur-

.rent from the runway or bridge conductors. The main-AUXILlARY GIRDER (OUTRIGGER): A glrder ar- line col/ectors are mounted on the bridge to transmitranged paral/el to the main girder for supporting the current from the runway conductors, and the trol/eyplatform, motor base, operator's cab, control panels, col/ectorsaremountedonthetrolleytotransmitcurrent

( tc., to reduce the torsional forces such load would from the bridge conductors.lerwise impose on the main girder.

CONTACTOR, MAGNETIC: An electro-rnagnetic de-BEARING LlFE EXPECTANCY: The L,o !ife of an vice for opening and closing an electric power circuitoanti-friction bearing is the minimum expected life, hours,of 90 percent of a group of bearings which are operat- CONTROLLER: A device for regulating in a pre-deter-ing at a given speed and loading. The average ex- mined way the power delivered to the motor or otherpected life of the bearings is approximately five times equipment.the L,o life.

COUNTER- TORQUE: A method of control by whichBHN: Brinell hardness number, measurement of mate- the motor is reversed to develop power to the oppositerial hardness. direction.

BOX SECTION: The rectangular cross section of gird- COVER PLA TE: The top or bottom plata of a boxers, trucks or other members enclosed on tour sides. girder.

BRAKE: A device. other than a motor, usad for retard- CROSS SHAFT: The shaft extending across the bridge,ing or stopping motion by friction or power means. (See used to transmit torque from motor to bridge driveSection 4.9) wheels.

BRANCH CIRCUIT: The circuit conductors between CUSHIONED ST ART: An electrical or mechanical~ final overcurrent device protecting the circuit and method for reducing the rate of acceleration of a travel:3 outlet(s). motion.

t¡[ BRIDGE: That pant of an overhead crane consisting of DEAD LOADS: The loads on a structure which remain ~

girders, trucks, end ties, walkway and drive mecha- in a fixed position relative to the structure. On a crane :nism which carries the trol/ey and travels in a direction bridge such loads include the girders, footwalk, crossparallel to the runway. shaft' drive units, panels, etc.

BRIDGE CONDUCTORS: The electrical conductors DEFLECTION: Displacement due to bending or twist-located along the bridge structure of a crane to provide ing in a vertical or lateral plane, caused by the imposed

.power to the trolley. live and dead loads.

BRIDGE RAIL: The rail supported by the bridge gird- DIAPHRAGM: A plate or partition between oppositeers on which the trolley travels. parts of a member, serving a definite purpose in the

structural design of the member.BUMPER (BUFFER): An energy absorbing device forreducing impactwhen a movingcraneortrolleyreac~es DRIVE GIRDER: The girder on which the bridge drivethe end of its pennitted travel, or when two movlng machinery is mounted.cranes or trolleys come into contacto

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DUMMY CAB: An operator's compartment or platform FOOTW ALK: The walkway with handrail anon a pendant or radio controlled crane, having no toeboards, attached m h brkige or troIley for ~c:permanently-mounted electrical controls, in which an purposes. ~

operator may ride while contro/ling the crane.GANTRY CRANE: A crane similar to an overhea

DYNAMIC LOWERING: A method of control by which crane except that the bridge for carrying the trolley <-the hoist motor is so connected in the lowering direc- trolleys is rigidly supported on two or more legs runnintion, that when it is over-hauled by the load, it acts as on fixed rails or other runway.a generator and forces current either through theresistors or back into the line. GIRDERS: The principal horizontal beams of the cran

bridge which supports the trolley and is supported bEDDY-CURRENT BRAKING: A method of control by the end trucks.which the motor drives through an electrical inductionload brake. GROUND FAULT: An accidental conducting connec

tion between the electrical circuit or equipment and th(EFFICIENCY OF GEARING AND SHEA VES: The earth or some conducting body that serves in place opercentage of force transmitted through these compo- the earth.nents that is not lost to friction.

HOIST: A machinery unit that is used for lifting ancELECTRIC OVERHEAD TRA VELING CRANE: An lowering a loadoelectrically operated machine for lifting, lowering andtransporting loads, consisting of a movable bridge HOLDING BRAKE: A brake that automatically pre-carrying a fixed or movable hoisting mechanism and vents motion when power is off.traveling on an overhead runway structure.

HOOK APPROACH: The minimum horiz6" .dis-ELECTRICAL BRAKING SYSTEM: A method of con- tance between the center of the runway ra~'tii1d thetrolling crane motor speed when in an overhauling hook.condition, without the use of friction braking.

IHYDRAULIC BRAKE: A brake that provides retardingENCLOSED CONDUCTOR (S): A conductor or group or stopping motion by hydraulic means.

Iof conductors substantially enc/osed to prevent acci-dental contacto IDLER SHEA VE: A sheave used to equalize tension in

opposite parts of a rape. Because of its slight move-ENCLOSURE: A housing to contain electrical compo- ment, it is not termed a running sheave.nents, usually specified by a NEMA classification num-ber. INDUSTRIAL DUTY CRANE: Service classification

covered by CMAA Specification No.70, "SpecificationsEND APPROACH: The minimum horizontal distance, for Electric Overhead Traveling Cranes".parallel to the runway, between the outermost extremi-ti es of the crane and the centerline of the hook. INSULA TION CLASS: Motor winding insulation rating

which indicates its ability to withstand heat and mois-END TIE: A structural member other than the end truck ture.which connects the ends of the girders to maintain thesquareness of the bridge. INVERTER (VARIABLE FREQUENCY DRIVE): A

method of control by which the fixed line voltynq andEND TRUCK: The unit consisting of truck trame, frequency is changed to a three-phase sys.~ withwheels, bearings, axles, etc., which supports the bridge infinitely variable voltage and frequency.

girders.ksl: Kips per square inch, measurement of stress

FAIL-SAFE: A provision designed to automatically intensity.stop or safely control any motion in which a malfunctionoccurs. KIP: A unit of force, equivalent to 1000 pounds.

FIELD WIRING: The wiring required after erection of KNEE BRACE: The diagonal structural member join-the crane. ing the building column and roof truss.

FIXED AXLE: An axle which is fixed in the truck and on LATERAL FORCES: Horizontal forces perpendicularwhich the wheel revolves. to the axis of the member being considered.

FLOOR-OPERA TED CRANE: A crane which is pen- LIFT: Maximum gafe vertical distance through whichdant contro/led by an operator on the floor or an the hook, magnet, or bucket can move.independent platform. i

LIFT CYCLE: Single lifting and lowering motion (withor without load).

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LIFTING DEVICES: Buckets, magnets, grabs and MILL DUTY CRANE: Service classification covered byother supplemental devices, the weight of which is to AlSE Standard No. 6, "Specification for Electric Over.

.be considered part of the rated load, usad for Base in head Traveling Cranes for Steel Mili Service'.handling certain types of loads.

MUL TIPLE GIRDER CRANE: A crane which has twoUMIT SWITCH: A device designad to cut off the power or more girders for supporting the live loadoautomatically at or near the limit of travel for the cranemotion. NON-COASTING MECHANICAL DRIVE: A drive with

coasting characteristics such that it will stop the motionUNE CONT ACTOR: A contactar to disconnect power within a distance in test equal to 10 percent of the ratedfrom the supply lines. speed in feet per minuta when traveling at rated speed

with rated loadoLIVE LOAD: A load which moves relative to the struc-ture under consideration. OPERA TOR'S CAB: The operator'scompartmentfrom

which movements of the crane are controlled. To beLOAD BLOCK: The assembly of hook, swivel, bear- specified by the manufacturer as open, having onlying, sheaves, pins and trame suspended by the hoist- sides or a railing around the operator, or enclosed,ing rapes. complete with roof, windows, etc.

LOAD CARRYING PART: Any part of the crane in OVERLOAD:Any load greater than the rated loadowhich the induced stress is influenced by the load onthe hook. OVERLOAD UMIT DEVICE: Refer to Section 4.3 for

a complete definition.LOAD CYCLE: One lift cycle with Joad plus one Jift

( ' ~ycle without loado OVERLOAD PROTECTION (OVERCURRENT): A

device operative on excessive current to cause and"- LONGITUDINAL STIFFENERS: Horizontal members maintain the interruption or reduction of current flow to

attached to the web of the bridge girder to prevent web the equipment governed.

buckling.PENDANT PUSHBUTTON STATION: Means sus-

MAGNETIC CONTROL: A means of controlling direc- pended from the crane operating the controllers fromtion and speed by using magnetic contactors and the floor or other level beneath the Grana.

relays.PITCH DIAMETER (ROPE): Distance through the

MAIN UNE CONT ACTOR: A magnetic contactar used center of a drum or sheave trom cantar to center of ain the incoming power circuit from the main line collec- rape passed about the periphery.torso

PLAIN REVERSING CONTROL: A reversing controlMAIN UNE DISCONNECT SWITCH: A manual switch which has identical characteristics for both directionswhich breaks the power lines leading from the main line of motor rotation.collectors.

PLUGGING: A control function which accomplishesMANUAL-MAGNETIC DISCONNECT SWITCH: A braking by reversing the motor tina voltage polarity orpowerdisconnecting means consisting of a magnetic phase sequence.contactar that can be operated by remate pushbutton

,d can be manually operated by a handle on the PROTECTIVE PANEL: An assembly containing over-.vVitch. load and undervoltage protection for all crane motions.

MASTER SWITCH: A manually operated device which QUAUFIED: A person who, by possession of a recog-serves to govem the operation of contactors and nized degree, certificate of professional standing orauxiliary devices of an electric control. who by extensive knowledge, training, and experi-

ence. has successfully demonstrated the ability toMATCH MARKING: Identification of non-interchange- salve or resolve problems relating to the subject matterable parts tor reassembly after shipment. and work.

MECHANICAL LOAD BRAKE: An automatic type of RA TED LOAD: The maximum load which the crane istriction brake usad for controlling loads in the lowering designed to handle safely as designated by the manu-direction. This unidirectional device requires torque facturer.trom the motor to lower a load but does not imposeadditionalload on the motor when fitting a loado REGENERATIVE BRAKING: A method ot controlling

speed in which electrical energy generated by theMEAN EFFECTlVE LOAD: A load used in durability motor is fed back into the power system.calculations accounting for both maximum and mini-mum loads.

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REGULA TED SPEED: A function which tends to main- STOP: A device to hit travel of a trolley or crant

tain constant motor speed tor any Ioad tor a given bridge. This device oonnaIy is attached lo a fDcec

speed setting of the controller. structure and normany does not have energy absorr

ing ability.REMOTE OPERA TED CRANE: A crane controlled byan operator not in a pulpit or in the cab attached to the STRENGTH, AVERAGE ULTIMA TE: The averag(crane, by any method other than pendant or rape tensile force per unit of cross sectional ares required tccontrol. rupture the material as detenTlined by test.

RESISTOR RA TING: Rating established by NEMA SWEEP: Maximum lateral deviation trom straightnesfwhich classifies resistors according to percent of ful/ of a structural member. measured at right angles to thE

load current on first point and duty cycle. Y-Yaxis.

ROTATING AXLE: An axle which rotates with the TEFC: Totally enclosed tan cooled.wheel.

TENV: Totally enclosed non ventilated.RUNNING SHEA VE: A sheave which rotates as thehook is raised or lowered. TORQUE, FULL LOAD (MOTOR): The torque pro-

duced by a motor operating at its rated horsepower andRUNWAY: The rails, beams, brackets and framework speed.on which the crane operates.

TORSIONAL BOX GIRDER: Girder in which the bridgeRUNW A y CONDUCTORS: The main conductors rail is located over one web.

mounted on or parallel to the runway which suppliescurrent to the crane. TORSIONAL FORCES: Forres which can ca'C vist-

ing of a member.RUNWAY RAIL: The rail supported by the runwaybeams on which the bridge travels. TROLLEY: The unit carrying the hoisting mechanism

which travels on the bridge rails.SHALL: This word indicates that adherence to theparticular requirement is necessary in arder to conform TROLLEY FRAME: The basic structure of fue trolleyto the specification. on which are mounted the hoisting and traversing

mechanisms.SHEA VE: A grooved wheel or pulley used with a rapeor chain to change direction and point of application of TWO BLOCKING: Condition under which fue loada pulling force. block or load suspended from the hook becomes

jammed against the crane structure preventing furtherSHOULD: This word indicates that the requirement is winding up of the hoist drum.a recommendation, the advisability of which dependson the facts in each situation. UNDERVOL TAGE PROTECTION: A device opera-

tive on the reduction or failure of voltage to cause andSKELETON CAB: Same as dummy cabo maintain the interruption of power in the main circuito

SKEWING FORCES: Lateral forces on the bridge VARIABLE FREQUENCY: A method of control bytruck wheels caused by the bridge girders not running which the motor SUPPIy voltage and frequency ('A "1 beperpendicular to the runways. Some normal skewing adjusted. loccurs in all bridges.

VOLTAGE DROP: The loss of voltage in an electricSPAN: The horizontal distance center-to-center of conductor between SUPPIy tap and load taporunway rails.

WEB PLA TE: The vertical plate connecting fue upperSTATIC CONTROL: A method of switching electrical and lower flanges or cover piates of a girder.circuits without the use of contacts.

WHEELBASE: Distance from center-to-center of out-STEPLESS CONTROL: A type of control system with ermost wheels.

ínfinite speed control between minimum speed and full

speed. WHEEL LOAD: The load without vertical inertia force~ on any wheel with the trolley and lifted load (rated

STEPPED CONTROL: A type of control system with capacity) positioned on the bridge to give maximum

fixed speed points. loading.

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70-8 INDEX.

Acceleration Factors 5.2.9.1.2.1 C ~ 4.12Acceleration Rate-Guide Table 5.2.9.1.2.1-A Cross Shatt-Bridge 4.11.2,4.11.3Acceleration Rate-Maximum Table 5.2.9.1.2.1-8 Deftedion 3.5.5AccessibiJity-Gontrol 5.10.2 Diaphragms 3.5.4Allowable StreSS-Structural 3.4 Disdaimer Page 1Allowable Stress-Shatt 4.11.4.1 Disconnect-Drive 5.6Allowable Stress-Gears 4.7.3 DraWlngs 1.12.1Anchors-Rope 4.6.2 Drives Bridge 4.10 and Table 4.10.1Assembly 1.10 Drum-Rope 4.6Bearings 4.8 Efficiency Table 5.2.9.1.1.1-1 and 5.2.9.1.1.1-2Bearing--Cross Shaft 4.11.2 Electrical Equipment 5.10.1Bearing Life 4.8.2 Endosure-Brake 5.4.7.3 (c)Block-Hoist 42 Endosure-Control 5.4.7Bolts-Structural 3.13 Endosure-Resistor 5.4.7.3 (b)Box Girder-Proportions 3.5.1 Endosure- Type 5.4.7.1Brake Bridge 4.9.4 and Figure 4.9.3 Enciosure-Ventilated 5.4.7.2Brake Hoist Holding 4.9.1 and 5.3.3 and 5.3.4 End TIeS 3.11Brake Trolley 4.9.3 and Figure 4.9.3 End Tnx:ks-8ridge 3.6 Figure 3.122-1Brake Electrical 4.9 and 5.3 Endurance Stress-Shatting 4.11.1Brake Enclosures 5.4.7.3 (c) Equaizer Trucks 3.11 and 3.12.1Brake Coil Time Rating 5.3.6 Erectm 1.13Brake DC Shunt 5.3.5 Euler Stress 3.4.8.2

( "ridge Acceleration Table 5.2.9.1.2. 1-A Fatigue-Shaft Endurance 4.11.1, ,ridge Conductors 5.11 Fatigue-Structural Stress Table 3.4.7-1

Bridge Drives- Type 4.10 and Figure 4.10.1 Fleel Angle 4.4.3Bridge Motors 5.2.9.1.2 Footwalk 3.7Bridge Wheels 4.13 Fridioo-Travel Wheel Tagle 5.2.9.12.1-DBuckling 3.4.8 Gantry Cranes 3.14Buckling Coefficient Table 3.4.8.2-1 Gears 4.7Bumpers 3.3.2.1.3.2 and 4.14 Gear Ratio-Hoist 5.2.10.1Building 1.2 and 1.3 Gear Ralio- Travel 5.2.10.2Cab-Operators 3.8 Gear Service Factors Table 4.7.3Camber-Girder 3.5.5 Girder-8ox-Proportions 3.5.1Capacity-Rated 1.6 Girder-8eam Box 3.5.8Classification of Cranes 2.0 thru 2.8 Girder-Single Web 3.5.7Clearance 1.3 Girder Torsion 3.5.6Codes-Referenced 1.1.6 Girder-Welding Figure 3.4.7-3Collectors 5.11.5 5.12.2 5.14.7 Glossary 70-7Collision Loads 3.3.2.4.3.2 Handrail 3.7Collision Forces-Bumpers 3.3.2.1.3.2 Hoisl Brakes 4.9.1Compression Member 3.4.6 Hoist Control Braking Means 4.9.2 and 5.4.4.1Contactor Rating AC SQuirrel Cage 5.4.5.2-2 Hoist load Factors 3.3.2.1.1.4.2

AC Wound Rotor 5.4.5.2-1 Hoist Motors 5.2.9.1.1DC 230 Volt 5.4.5.2-3 Hoisl Ropes 4.4

! :Jntrol-Magnetic 5.4.5 Hooks 4.2.2

Conlrol-Remote 5.4.3 Hook Blocks 4.2Control-Static 5.4.6 Impad (See VIF)Controllers-Arrangement Figure 5.7.3 and 5.7.4 Inspection 1.15Controllers-AC and DC 5.4 Inverters (Variable FreQuency Drives) 5.14Controllers-Bridge 5.4.4.2 Leg-Gantry 3.14Conlrollers-Hoist (with control braking means) 5.4.4.1 Life-Bearing 4.8.2Controllers- Trolley 5.4.4.2 Umit Device-Overload 4.3

Umit Switch 5.9

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Loads 3.3.2 RmwayTdel'ances Table 1.42.1Load Block 42 Serva ~ Table 2.8-1Load Combinatk>n 3.3.2.4 Shafting ..11Load Factor-Dead 3.3.2.1.1.4.1 Shafting-Bridge Cross Shaft 4.11.2Load Factor-Hoist 3.3.2.1.1.4.2 Shafting Endurance Stress 4.11.1Load-Mean Effective 4.1 Shaft Angular Deflection 4.11.3Load Principal 3.3.2.1.1 Sheave 4.5Load Spectrum 2.1 Sheave-ldler 4.5.3Longitudinal Stiffeners 3.5.2 Skewing Forces 3.3.2.1.2.2Lubrication 1.14,4.7.6,4.7.7,4.8.4 Speed-Floor Control Figure 6.2Machinery Service Factors Table 4.1.3 Cab Control Figure 6.3Magnet Control 5.7.6 Standards-Referenced 1.1.6Magnetic Control 5.4.5 Stability Analysis 3.4.5Main Une Contactar 5.6.6 Stiffened Plates 3.5.3Maintenance 1.15 Stiffener-longitudinal Web 3.5.2Master Switches 5.7 Stiffener-Vertical 3.5.4Material-5tructural 3.1 Stress-A/lowable Structural 3.4Mechanical Load Brake 4.9.1.2.2 and 4.9.1.5.2 Stress-Allowable Shaft 4.11.4Molten Metal Crane 4.4.1 Stress-A/lowable Range 3.4.8Motors 5.2 Stress-combined 3.4.4 and 4.1 1 .4.1 EMotor Hoist 5.2.9.1.1 Stress Concentration Factors 4.1.4Motor Travel 52.9.1.2 Testing 1.11Operator 1.15 Ties-End 3.11Operators Cab 3.8 Torsior).-80x Girders 3.3.2.2.1,3.5.6Outdoor-Bridge Drive Power 5.2.9.1.2.3 Beam Box Girders 3.5.8Overload Umit Device 4.3 Torsion-Cross Shaft Deflection Table 4.11.3-1Paint 1.9 Tro/ley Bumper 4.14.7Protection-Electrical 5.6 Trolley Frame 3.9Pushbutton Pendant 5.8 Figure 5.8.1 Truck 3.6 Figure 3.12.2-1Proportions-Box Girder 3.5.1 VIF (Verticallnertia Forces) 1.4.3, 3.3.2.1. 4, 4.1.1, 4.13.3Rail-Bridge 3.10 Vo/tage Drop 5.13Rail Clips Figure 3.4.7-4 Warning Devices 5.6.15Railing 3.7 Weld Stress 3.4.4.2Radio Control 5.6.12,5.8.1, Figure 5.8. 1-C Welding 3.2, Figure 3.4.7-3, Figure 3.4.7-4Remote Control 5.4.3 Wheels 4.13Resistors 5.5, 5.4.5.3 Wheel Load Longitudinal Distribution 3.3.2.3Resistor Enclosure 5.4.7.3 (b) Wheels-Multiple Arrangements 3.12Rope Anchor 4.6.2 Wheel Loads 4.13.3Rope Drum 4.6 Wheel Load Factors Table 4.13.3.1Rope--Hoist 4.4 Wheel Sizing 4.13.3, Table 4.13.3-4Rope--Fleet Angle 4.4.3 Wheel Skidding-Maximum Acceleration Rate 5.2.9.1.2. 1-BRope--Sheaves 4.5 Wheel Speed Factor Table 4.13.3-2Runway 1.4 Wind Loads 3.3.2.1.2.1, 3.3.2.1.3.1, 5.2.9.1.2.3Runway Conductor 1.5, 5.12, 5.14.7

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~@ 2000 An Affiliateof(3) Cm A A f. Material Handling Indus!:-¡

8720 Red Oak Blvd.. Suite 201

Charlolte. NC 28217-3992CRANE MANUFACTURERS Telephone: (704) 676-1 i90ASSOCIATION OF AMERICA. INC FAX: (70/~i 676-1199 SK $q:

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